PETROLEUM PROVINCE PETROLEUM PROVINCE AND SEDIMENTARY AND SEDIMENTARY

BASINSBASINS

Presented ByhelliphellipPresented Byhelliphellip

Jawad Bashir (Thunder)Jawad Bashir (Thunder)

GROUP MEMBERSGROUP MEMBERS

bull ARSAL(THEETA)

bull TAUSEEF ABBASI

bull HAMMED (HAMMI)

bull ABDUL REHMAN QAZI

bull BAQIR(MONI)

PROVINCEPROVINCE

bull A spatial entity with geomorphic and geologic attributes

bull A province may include a single dominant structural element (basin fold belt) or a number of contiguous related elements

bull There are a particularly large number of provinces identified worldwide for petroleum and other minerals

CHARACTERSTICS OF CHARACTERSTICS OF PROVINCEPROVINCE

bull Characterized by similar features

bull Nature of organic matter and thermal history

bull Include several Petroleum Zones

bull Contain different Lithologies of Various ages

Provinces ClassificationProvinces Classification

bull There are two types of province Classification

bull On the bases of Origin

bull On the bases of Tectonic and Lithological settings

ON BASES OF ORIGIONON BASES OF ORIGION

bull Shield

bull Platform

bull Large Igneous Province

bull Basin

bull Extended Crust

bull Orogen

LITHOLOGICAL AND TECTONICLITHOLOGICAL AND TECTONIC

1 Depositional or emplacement rock packages

2 Overprinting provinces

3 Composite rock packages

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

GROUP MEMBERSGROUP MEMBERS

bull ARSAL(THEETA)

bull TAUSEEF ABBASI

bull HAMMED (HAMMI)

bull ABDUL REHMAN QAZI

bull BAQIR(MONI)

PROVINCEPROVINCE

bull A spatial entity with geomorphic and geologic attributes

bull A province may include a single dominant structural element (basin fold belt) or a number of contiguous related elements

bull There are a particularly large number of provinces identified worldwide for petroleum and other minerals

CHARACTERSTICS OF CHARACTERSTICS OF PROVINCEPROVINCE

bull Characterized by similar features

bull Nature of organic matter and thermal history

bull Include several Petroleum Zones

bull Contain different Lithologies of Various ages

Provinces ClassificationProvinces Classification

bull There are two types of province Classification

bull On the bases of Origin

bull On the bases of Tectonic and Lithological settings

ON BASES OF ORIGIONON BASES OF ORIGION

bull Shield

bull Platform

bull Large Igneous Province

bull Basin

bull Extended Crust

bull Orogen

LITHOLOGICAL AND TECTONICLITHOLOGICAL AND TECTONIC

1 Depositional or emplacement rock packages

2 Overprinting provinces

3 Composite rock packages

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

PROVINCEPROVINCE

bull A spatial entity with geomorphic and geologic attributes

bull A province may include a single dominant structural element (basin fold belt) or a number of contiguous related elements

bull There are a particularly large number of provinces identified worldwide for petroleum and other minerals

CHARACTERSTICS OF CHARACTERSTICS OF PROVINCEPROVINCE

bull Characterized by similar features

bull Nature of organic matter and thermal history

bull Include several Petroleum Zones

bull Contain different Lithologies of Various ages

Provinces ClassificationProvinces Classification

bull There are two types of province Classification

bull On the bases of Origin

bull On the bases of Tectonic and Lithological settings

ON BASES OF ORIGIONON BASES OF ORIGION

bull Shield

bull Platform

bull Large Igneous Province

bull Basin

bull Extended Crust

bull Orogen

LITHOLOGICAL AND TECTONICLITHOLOGICAL AND TECTONIC

1 Depositional or emplacement rock packages

2 Overprinting provinces

3 Composite rock packages

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

CHARACTERSTICS OF CHARACTERSTICS OF PROVINCEPROVINCE

bull Characterized by similar features

bull Nature of organic matter and thermal history

bull Include several Petroleum Zones

bull Contain different Lithologies of Various ages

Provinces ClassificationProvinces Classification

bull There are two types of province Classification

bull On the bases of Origin

bull On the bases of Tectonic and Lithological settings

ON BASES OF ORIGIONON BASES OF ORIGION

bull Shield

bull Platform

bull Large Igneous Province

bull Basin

bull Extended Crust

bull Orogen

LITHOLOGICAL AND TECTONICLITHOLOGICAL AND TECTONIC

1 Depositional or emplacement rock packages

2 Overprinting provinces

3 Composite rock packages

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Provinces ClassificationProvinces Classification

bull There are two types of province Classification

bull On the bases of Origin

bull On the bases of Tectonic and Lithological settings

ON BASES OF ORIGIONON BASES OF ORIGION

bull Shield

bull Platform

bull Large Igneous Province

bull Basin

bull Extended Crust

bull Orogen

LITHOLOGICAL AND TECTONICLITHOLOGICAL AND TECTONIC

1 Depositional or emplacement rock packages

2 Overprinting provinces

3 Composite rock packages

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

ON BASES OF ORIGIONON BASES OF ORIGION

bull Shield

bull Platform

bull Large Igneous Province

bull Basin

bull Extended Crust

bull Orogen

LITHOLOGICAL AND TECTONICLITHOLOGICAL AND TECTONIC

1 Depositional or emplacement rock packages

2 Overprinting provinces

3 Composite rock packages

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

LITHOLOGICAL AND TECTONICLITHOLOGICAL AND TECTONIC

1 Depositional or emplacement rock packages

2 Overprinting provinces

3 Composite rock packages

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

TYPES OF ORIGIN PROVINCESTYPES OF ORIGIN PROVINCES

SHIELDSHIELDbull A shield is generally a large area of exposed

Precambrian crystalline igneous and high-grade metamorphic rocks

bull Forms a tectonically stable area

bull Age of these rocks is greater than 570 million years to 2 to 35 billion years

bull A shield is that part of the continental crust in which these usually Precambrian basement rocks crop out extensively at the surface

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

PLATFORMPLATFORM

bull In geology a platform is a continental area covered by flat sedimentary strata overlie a basement of consolidated igneous or metamorphic rocks

bull Many oilfields produce from sediments deposited along carbonate platforms

bull Common along passive margins

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

OROGENOROGENbull A linear or arcuate region that

has been subjected to folding and other deformation during an orogenic cycle

bull Refers to the process of natural mountain building

bull The process of orogeny can take tens of millions of years and build mountains from plains to ocean floors

bull Orogeny can occur due to continental collision or volcanic activity

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

TYPES OF OROGENTYPES OF OROGEN

1 Island arc

2 Continental arc

3 Forearc

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Large Igneous ProvinceLarge Igneous Province

bull Large accumulation of igneous rocks

bull Both intrusive or extrusive

bull Extending over areas greater than 100000 square kilometers

bull LIP include continental flood basalts oceanic plateaus large dike swarms and volcanic rifted margins

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

EXTENDED CRUST EXTENDED CRUST

bull A province of thinned crust (gt50 ) due to extension eg The Basin amp Range North America

bull Extended crusts are further divided into

1 Rift Margins

2 Rift

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Rift MarginsRift Margins

bull Separated continental tracts move perpendicular to the coastline

bull Normal faults associated with it

bull Further Divided into two Types

1 Non Volcanic Rift Margins2 Volcanic Rift Margins

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Rifts Rifts

bull A rift is a place where the Earths crust and lithosphere are being pulled apart

bull Produce due to extensional phenomena

bull Horst and Grabon structures are prominent characteristic feature

bull Most rifts occur along the central axis of a mid-ocean ridges

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

BasinBasin

bull A low area in the Earths crust of tectonic origin in which sediments have accumulated

bull Basins are further divided into

1 Cratonic Basin

2 Foredeep Basin

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Depositional Or Emplacement rock Depositional Or Emplacement rock PackagesPackages

bull Depositional and Emplacement rock packages contain two major province types

1 Sedimentary Provinces

2 Igneous Provinces

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Sedimentary ProvincesSedimentary Provinces

bull A sedimentary province (or basin) is an accumulation of sedimentary rocks with or without volcanics

bull whose lateral boundaries may be structural depositional erosional or interpreted

bull Characterized on basis of a distinct tectonic and depositional history

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Igneous ProvinceIgneous Province

bull Igneous provinces are temporally and geographically cohesive packages of igneous rocks

bull May be compositionally heterogeneous

bull Some igneous provinces may have formed in a geologically brief period other over a long period

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Overprinting provincesOverprinting provinces

bull Over printing provinces mean provinces which formed as a result of over printing or over lying of another strata

bull Divided into four further types

1 Structural provinces2 Metamorphic provinces (regional and

contact metamorphism)3 Metallogenic provinces4 Regolith-landform provinces

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Structural provinceStructural provincebull Structural provinces are

the spatial representation of the extent of deformation events

bull Structural provinces typically overprint igneous or sedimentary provinces but may also overprint older structural and metamorphic provinces

bull A structural province may consist of the effects of one or more deformation events

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Metamorphic Provinces andMetamorphic Provinces and Metallogenic Provinces Metallogenic Provinces

bull Metamorphic Province

A metamorphic province represents the spatial extent of one or more metamorphic events

Temporal continuity of metamorphic events should be established

bull Metallogenic Province An area characterized by a particular assemblage of mineral occurrences

Metallogenic provinces are thought to be formed also by the expulsion of pore waters from sedimentary basins

Metallogenic provinces may include the mineralized parts of one or more mineral systems

bull Diverse commodities and deposit styles may be linked within a single mineral system

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Regolith-landform provinceRegolith-landform province

bull No strict definition of regolith-landform provinces currently exists

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Composite rock packagesComposite rock packagesbull Composite rock packages

only contain Tectonic province

bull Groups of provinces linked by a common tectonic history are designated as tectonic provinces

bull Tectonic provinces may contain a collection of sedimentary igneous structural metamorphic and metallogenic provinces

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Typical Petroleum ProvinceTypical Petroleum Province

bull The concept of a petroleum province was first suggested by Perrodon (1980)

bull Petroleum province composed of one or several sedimentary basins having common geological features and a comparable history

bull The classic petroleum provinces are still the worlds major producers of hydrocarbons

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

GIANT PETROLEUM PROVINCEGIANT PETROLEUM PROVINCE

bull Nehring(1978) and Perrodon(1978)pointed out about 20 giant province

bull Contain over 85 of the total production plus recoverable reserves of conventional oil

bull However these provinces cover only 20 of the total surface of sedimentary basins

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

SEDIMENTARY BASINSSEDIMENTARY BASINS

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

BASINBASIN

bull The official definition of a sedimentary basin is a low area in the Earthrsquos crust of tectonic origin in which sediments accumulate

bull Sedimentary basins range in size from as small as hundreds of meters to large parts of ocean basins

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

PRACTICAL THINGS IN BASINSPRACTICAL THINGS IN BASINS bull Master cross sections with the present land surface as the most

natural datum construct several detailed physical cross sections through the basin to show its geometry and sediment fill

bull Stratigraphic sections construct a graph with time along the vertical axis showing the time correlations of all the major rock units along some generalized traverse across the basin Such a section includes hiatuses during which there was nondeposition or erosion

bull Isopach maps with some distinctive stratigraphic horizon near the top of the section as datum draw a contour map showing isopachs (isopachs are loci of equal total sediment thickness) in the basin

bull Lithofacies maps for one or a series of times draw a map showing distri-bution of sediment types being deposited at that time

bull Ratio maps compute things like sandshale ratio integrated over the entire section or restricted to some time interval and plot a contour map of the values

bull Paleocurrent maps for one or a series of times draw a map showing the direction of paleocurrents in the basin at that time

bull Grain-size maps for the entire basin fill averaged vertically or for some stratigraphic interval or time interval draw a map that shows the areal distribution of sediment grain size This is especially useful for conglom-eratic basins

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

THINGS TO WATCH ON FIELDTHINGS TO WATCH ON FIELD

bull Cross-stratification

bull Bed forms

bull Clast orientation

bull Sole marks

bull Parting lineation

bull Paleocurrent measurements

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

HOW BASINS ARE MADEHOW BASINS ARE MADE

bull Following are the phenomena

1 Local

2 Regional

3 Thermal

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

LOCAL AND REGIONALLOCAL AND REGIONAL

bull LOCAL

On a small scale

Fault movements can create relief of hundreds to thousands of meters resulting in small but often deep basins

bull REGIONAL

bull Basin relief can be created mechanically on a regional scale in two very important ways thermally or flexurally or by a combination of those two effects

bull Basins can also be made just by making mountain ranges on land or in the ocean by volcanism

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

THERMALTHERMALbull If the lithosphere is heated from below it expands

slightly and thus becomes less dense

bull Earthrsquos surface as crustal uplifts

bull Isostatic subsidence produced when crust cool backs

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

CLASSIFICATION OF CLASSIFICATION OF SEDIMENTARY BASINSSEDIMENTARY BASINS

bull Sedimentary basins are classified on the bases of different unique characteristics

1 Nature of fill

2 Geometry

3 Paleogeography

4 Tectonic setting

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Mechanisms of BasinMechanisms of BasinFormationFormation

1 Isostatic

2 Loading

3 Dynamic

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Mechanisms of BasinMechanisms of BasinFormationFormation

bull 1048708 Isostatic Processes

Crustal thinning1048708Extensional stretching erosion during uplift magmatic

withdrawal

Mantle-Lithosphere Thickening1048708Cooling of lithosphere following cessation of stretching or

cessation of heating

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Isostatic ProcessesIsostatic Processes

Crustal densification

Density increase due to changing

pressuretemperature conditions andor

emplacement of higher density melts into

lower density crust

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

LoadingLoading

Sedimentary or Volcanic LoadingTectonic loading During over thrusting andor under pulling

Subcrustal loadingbull Lithospheric flexure during under thrusting

of dense lithosphere

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Sedimentary Basins amp Sedimentary Basins amp Petroleum GeologyPetroleum Geology

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Controls on large-scale Controls on large-scale sedimentationsedimentation

bull Sedimentary processes are controlled on large scales by

bull Climate ndash determines

bull weathering rates bull precipitation amp run-off (sed transportation) bull environments

bull Tectonic setting ndash determines

bull relief bull time for sed transport bull types of environments bull types of sedimentary basins bull source rock type

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

What is a sedimentary basinWhat is a sedimentary basin

bull A low area on the Earthrsquos surface relative to surroundings ndash eg deep ocean basin (5-10 km deep) intramontane basin (2-3 km

asl) bull May be of tectonic (or erosional origin) bull A receptacle for sedimentation erosion may also be important bull Sedimentation may be interrupted - unconformities bull Basins may be small (kms2) or large (106+ km2) bull Basins may be simple or composite (sub-basins) bull Basins may change in size amp shape due to

ndash erosion ndash sedimentation ndash tectonic activity ndash eustatic sea-level changes

bull Basins may overlap each other in time

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

The Evolution of Sedimentary The Evolution of Sedimentary BasinsBasins

bull The evolution of sedimentary basins may include ndash tectonic activity (initiation termination) ndash magmatic activity ndash metamorphism

bull as well as sedimentation bull all may be contemporaneous bull Basins may develop on oceanic crust

island arc crust or continental crust

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

bull Basins may be sedimentary basins ndash sedimentary fill is relatively undeformed ndash basin margin facies are preserved

bull OR structural (remnants of) basins ndash sedimentary fill is deformed ndash dips gt original depositional slopesndash basin margin facies are eroded

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Components of a basinComponents of a basin

bull Axial elements of sedimentary basins ndash Basin axis is the lowest point on the

basement surface ndash Topographic axis is the lowest point on the

depositional surface ndash Depocentre is the point of thickest sediment

accumulation

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

What type of basin do we haveWhat type of basin do we have

bull Depends on the structural setting of the basin

bull Many types corresponding to different locationsndash Divergent plate margin basinsndash Convergent plate margin basins

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Divergent plate Divergent plate margin basinsmargin basins

bull Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)bull Aulacogene BasinsAulacogene Basins

bull Continental Rift ZonesContinental Rift Zonesbull Oceanic Rift BasinsOceanic Rift Basins

bull Open Ocean Passive-Margin BasinsOpen Ocean Passive-Margin Basins

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Origin ndash large scale mantle convection ndash regional updoming plusmn regional basaltic (flood)

volcanism

bull extensional failure of crust ndash listric normal fault system ndash subsidedrotated half grabens

bull widening to form central rift graben ndash may

bull rupturing of crust bull spreading ridge oceanic basin

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull two associated basin types ndash central rift graben basin ndash rim basins

bull environments amp facies ndash alluvial fan fluvial lake ndash volcanism

bull initial (flood) basaltic (arch phase) ndash lavas

bull intra-rift bimodal volcanism ndash basalt-rhyolite lavas amp pyroclastics ndash often peralkaline ndash calderas stratovolcano shields ndash mantle magmas melt crust

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Rift Zones (Narrow)Continental Rift Zones (Narrow)

bull Sediment compositions ndash mixed provenance ndash exposed crustal rocks at rift margin ndash contemporaneous volcanic sources

bull Examples ndash East Africa rift zone ndash Rio Grande rift Rhine graben

bull May be subsequently deformed by compressional deformation ndash eg Proterozoic Mt Isa rift ndash Devono-Carb Mt Howitt province Victoria

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Aulacogene BasinsAulacogene Basins

bull Narrow continental rifts which do not evolve into spreading ridge oceanic basins ndash eg North Sea basins Europe Gippsland Basin Bass Basin

bull Dominated by initial alluvial fan fluvial lake facies up to 4 km thick bull May extend through

ndash crustal subsidence amp extension ndash marine transgression no oceanic crust ndash coastal plain rivers coal swamp shoreline shelf amp slope environment

(eg Gippsland Bass basins bull Provenance

ndash continental mixed ndash plutonic metasedimentary metavolcanic contemporaneous volcanic ndash plusmn marine carbonates

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Rift ZonesContinental Rift Zones

bull Origin ndash regionally extensive mantle convection ndash = driven by subduction oceanic spreading ridge under continent ndash eg Western USA

bull Extensional failure of crust ndash complex lystric fault system

bull down to 15 km Western USA ndash uprise of mantle + metamorphic core complexes - regional uplift up to 2-3 km ndash widespread volcanism in complex multiple graben rift basins

bull Environments and facies ndash alluvial fan fluvial lacustrine

bull Volcanism ndash flood basalts bimodal basalt-rhyolite-andesite lavas amp pyroclastics ndash tholeiitic alkaline calc-alkaline lavas amp pyroclastics

bull Provenance ndash mixed crustal sources ndash contemporaneous volcanic sources

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Oceanic Rift BasinsOceanic Rift Basinsbull Initially narrow (eg Red Sea) bull may evolve into open oceanic basins

bull Origin ndash narrow continental rifts evolve ndash break-up ndash oceanic spreading ridge ndash oceanic crust in axial basins ndash continental crust at basin margin

bull Environments amp facies ndash alluvial fans fan deltas shoreline narrow shelf slope abyssal plain

bull Volcanism ndash MORB tholeiitic oceanic crust ndash Lavas hyaloclastite

bull Provenance ndash mixed continental ndash contemporaneous volcanics ndash shelf carbonate evaporites ndash oceanic carbonate evaporites ndash oceanic pelagic hemi-pelagic

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Open Ocean Passive-Margin Open Ocean Passive-Margin BasinsBasins

bull Evolve from oceanic rift basins bull Become passive margin basins when MORrsquos - large wide ocean

basins bull Half graben system evolves into coastal plain-continental shelf amp

slope ndash oceanic abyssal plain system

bull Volcanism ndash none expected after break-up ndash perhaps intraplate hot spot volcanism

bull Sedimentation amp provenance ndash as for oceanic rift basin ndash + well developed shelf-slope seds (plusmn carbonate seds)

bull Tectonics ndash post-break-up thermal amp later isostatic subsidence of continental margin

bull transgression

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Convergent Plate Convergent Plate Margin BasinsMargin Basins

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Origin ndash oceanic plate being subducted under continental

margin ndash trench accretionary prism continental margin

volcanic arc ndash Eg Andes Cascades arc

bull Volcanism ndash calc-alkaline arc volcanism

bull andesites dacites rhyolites rhyodacites minor basalts bull hydrous fluids from subducting lab melt mantle above amp both

then melt the base of the crust bull lavas + pyroclastics

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Basin types environments amp facies bull Trench basin

ndash deep marine ndash turbidites pelagic seds

bull Forearc basin ndash perched on scraped off imbricate thrust faulted accretionary prism ndash alluvial fan fluvial shoreline shelf deep turbidite fans

bull Back arc-foreland basin ndash lies behind arc ndash at foot of craton directed fold amp thrust belt if present ndash alluvial fan fluvial lakes

bull Intra-arc ndash arc volcanoes often lie in major graben ndash alluvial fan fluvial lake

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Margin Arc-Subduction Continental Margin Arc-Subduction Associated BasinsAssociated Basins

bull Sediment compositions ndash Trench

bull metasedimentary debris eroded off accretionary prism bull v minor volcanic debris bull pelagic sed

ndash Forearc basin bull voluminous volcanic debris

ndash Back-arc basin bull arc amp thrust belt derived bull mixed volc meta-sed metamorphic plutonic

ndash Intra-arc basins lavas volcanic seds pyroclastics

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Eg Marianas Tonga-Kermadec arcs bull Origin

ndash oceanic plate is subducted under another oceanic plate ndash trench accretionary prism volcanic island arc ndash volcanic arc on oceanic lithosphere ndash back arc basin(s) originate by rifting of arc block development of

small spreading ridge bull widening basin oceanic crust

ndash arc block migrates trenchward as subducting plate rolls back

bull Volcanism ndash island arc tholeiitic volcanics

bull basalts basaltic andesites

ndash back arc basin tholeiitic crust

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Island Arc-Subduction Associated Island Arc-Subduction Associated BasinsBasins

bull Basin types environments facies provenance bull Trench basin

ndash turbidites pelagic sediments ndash metasedimentary sed from accretionary prism ndash arc derived volcanic sediment

bull Fore-arc basin ndash on accretionary prism ndash volcanic seds carbonates ndash turbidites

bull Back arc basin ndash arc derived volcaniclastic turbidite apron ndash pelagic sediments especially where basin is large

bull no continental derived sediment bull only rare silicic volcanism

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Collision Belts amp BasinsContinental Collision Belts amp Basins

bull Eg Himalayan mountain chain European Alps

bull Origin ndash long term subduction of oceanic plate under continental margin will bring

passenger continent into collision with arc host continent ndash oceanic basin closes during collision ndash subducting continent under thrust over-riding continent ndash uplift mountain range double continental crust thickness

bull Volcanism ndash subduction related volcanism stop at collision when subduction stop ndash granitoid plutonism may occur due to extremely thickened crust

bull magmas wont rise because of compressional stress field

bull Basin types environments facies provenance ndash foreland basin at foot of fold amp thrust belt ndash subject to isostatic subsidence ndash huge sediment flux off mountain belt ndash alluvial fan braided river meandering river lake environments amp facies ndash metasedimentary met (include high grade plutonic reflecting deep crustal

erosion)

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Continental Strike-Slip BasinsContinental Strike-Slip Basins

bull Eg California borderland basins associated with San Andreas strike-slip fault system

bull Origin ndash strike-slip along non-linear faults ndash opening holes or basins at fault jogs or bends

bull Volcanism ndash usually none unless accidental intraplate

bull Basin types environments facies provenance ndash pull-apart or strike-slip basins ndash alluvial fans rivers lakes ndash alluvial lacustrine coal evaporite seds ndash provenance whatever is being eroded from exposed crust

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites

Stable Continental Interior BasinsStable Continental Interior Basins

bull Eg Lake Eyre Basin

bull Intracratonic (= within stable continental crustal mass)

bull Long term stability

bull Flat topography

bull River desert lake environments amp facies

bull Mature basement derived sed plusmn evaporites