17156896 Sedimentary Basins Petroleum Geology

8/9/2019 17156896 Sedimentary Basins Petroleum Geology

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Sedimentary Basins &Sedimentary Basins &

Petroleum GeologyPetroleum Geology


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Controls on largeControls on large--scalescale

sedimentationsedimentation Sedimentary processes are controlled, on large scales,Sedimentary processes are controlled, on large scales,

by:by:

ClimateClimate determines:determines:

weathering rates,weathering rates, precipitation & runprecipitation & run--off (sed. transportation),off (sed. transportation),

environmentsenvironments

Tectonic settingTectonic setting determines:determines:

reliefrelief

time for sed. transporttime for sed. transport

types of environmentstypes of environments

types of sedimentary basinstypes of sedimentary basins

source rock typesource rock type


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What is a sedimentary basin?What is a sedimentary basin?

A low area on the Earths surface relative to surroundingsA low area on the Earths surface relative to surroundings e.g. deep ocean basin (5e.g. deep ocean basin (5--10 km deep), intramontane basin (210 km deep), intramontane basin (2--3 km3 km

a.s.l.)a.s.l.)

May be ofMay be oftectonictectonic (or(orerosionalerosional origin)origin)

A receptacle for sedimentation; erosion may also be importantA receptacle for sedimentation; erosion may also be important

Sedimentation may be interruptedSedimentation may be interrupted -- unconformitiesunconformities Basins may be small (kms2) or large (106+ km2)Basins may be small (kms2) or large (106+ km2)

Basins may be simple or composite (subBasins may be simple or composite (sub--basins)basins)

Basins may change in size & shape due to:Basins may change in size & shape due to: erosionerosion

sedimentationsedimentation tectonic activitytectonic activity

eustatic seaeustatic sea--level changeslevel changes

Basins may overlap each other in timeBasins may overlap each other in time


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The Evolution of SedimentaryThe Evolution of Sedimentary

BasinsBasins The evolution of sedimentary basins mayThe evolution of sedimentary basins may

include:include:

tectonic activity (initiation, termination)tectonic activity (initiation, termination)

magmatic activitymagmatic activity

metamorphismmetamorphism

as well as sedimentationas well as sedimentation

all may be contemporaneousall may be contemporaneous Basins may develop on oceanic crust,Basins may develop on oceanic crust,

island arc crust, or continental crustisland arc crust, or continental crust


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Basins may be sedimentary basinsBasins may be sedimentary basins

sedimentary fill is relatively undeformed,sedimentary fill is relatively undeformed,

basin margin facies are preservedbasin margin facies are preserved OR,OR, structuralstructural (remnants of)(remnants of) basinsbasins

sedimentary fill is deformedsedimentary fill is deformed

dips > original depositional slopesdips > original depositional slopes basin margin facies are erodedbasin margin facies are eroded


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Components of a basinComponents of a basin

Axial elements of sedimentary basins:Axial elements of sedimentary basins:

Basin axisBasin axis is the lowest point on theis the lowest point on the

basement surfacebasement surface

Topographic axisTopographic axis is the lowest point on theis the lowest point on the

depositional surfacedepositional surface

DepocentreDepocentre is the point of thickest sedimentis the point of thickest sediment

accumulationaccumulation


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What type of basin do we have?What type of basin do we have?

Depends on the structural setting of theDepends on the structural setting of the

basinbasin

Many types, corresponding to differentMany types, corresponding to differentlocationslocations

Divergent plate margin basinsDivergent plate margin basins

Convergent plate margin basinsConvergent plate margin basins


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Divergent plate marginDivergent plate margin

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

Aulacogene BasinsAulacogene Basins

Continental Rift Zones

Continental Rift Zones

Oceanic Rift BasinsOceanic Rift Basins

Open Ocean PassiveOpen Ocean Passive--Margin BasinsMargin Basins


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

OriginOrigin large scale mantle convectionlarge scale mantle convection

regional updomingregional updoming ss regional basaltic (flood)regional basaltic (flood)

volcanismvolcanism extensional failure of crustextensional failure of crust

listric normal fault systemlistric normal fault system

subsided/rotated half grabenssubsided/rotated half grabens

widening to form central rift grabenwidening to form central rift graben may:may:

rupturing of crustrupturing of crust

spreading ridge, oceanic basinspreading ridge, oceanic basin


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two associated basin typestwo associated basin types central rift graben basincentral rift graben basin

rim basinsrim basins

environments & faciesenvironments & facies

alluvial fan, fluvial, lakealluvial fan, fluvial, lake volcanismvolcanism

initial (flood) basaltic (arch phase)initial (flood) basaltic (arch phase) lavaslavas

intraintra--rift bimodal volcanismrift bimodal volcanism

basaltbasalt--rhyolite lavas & pyroclasticsrhyolite lavas & pyroclastics often peralkalineoften peralkaline

calderas, stratovolcano, shieldscalderas, stratovolcano, shields

mantle magmas melt crustmantle magmas melt crust


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Sediment compositionsSediment compositions mixed provenancemixed provenance

exposed crustal rocks at rift marginexposed crustal rocks at rift margin

contemporaneous volcanic sourcescontemporaneous volcanic sources

ExamplesExamples East Africa rift zoneEast Africa rift zone

Rio Grande rift; Rhine grabenRio Grande rift; Rhine graben

May be subsequently deformed byMay be subsequently deformed by

compressional deformationcompressional deformation e.g. Proterozoic Mt. Isa rifte.g. Proterozoic Mt. Isa rift

DevonoDevono--Carb. Mt. Howitt province, VictoriaCarb. Mt. Howitt province, Victoria


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Aulacogene BasinsAulacogene Basins

Narrow continental rifts which do not evolve into spreading ridgeNarrow continental rifts which do not evolve into spreading ridgeoceanic basins.oceanic basins. e.g North Sea basins, Europe; Gippsland Basin, Bass Basin.e.g North Sea basins, Europe; Gippsland Basin, Bass Basin.

Dominated by initial alluvial fan, fluvial, lake facies; up to 4 km thick.Dominated by initial alluvial fan, fluvial, lake facies; up to 4 km thick.

May extend throughMay extend through crustal subsidence & extensioncrustal subsidence & extension marine transgression; no oceanic crustmarine transgression; no oceanic crust

coastal plain rivers, coal swamp shoreline, shelf & slope environmentcoastal plain rivers, coal swamp shoreline, shelf & slope environment(e.g. Gippsland, Bass basins(e.g. Gippsland, Bass basins

ProvenanceProvenance continental, mixedcontinental, mixed

plutonic, metasedimentary, metavolcanic, contemporaneous volcanicplutonic, metasedimentary, metavolcanic, contemporaneous volcanic ss marine carbonatesmarine carbonates


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Continental Rift ZonesContinental Rift Zones

OriginOrigin regionally extensive mantle convectionregionally extensive mantle convection

= ? driven by subduction oceanic spreading ridge under continent= ? driven by subduction oceanic spreading ridge under continent

e.g. ?Western U.S.A.e.g. ?Western U.S.A.

Extensional failure of crustExtensional failure of crust

complex

lystric fault systemcomplex

lystric fault system down to 15 km, Western U.S.A.down to 15 km, Western U.S.A.

uprise of mantle + metamorphic core complexesuprise of mantle + metamorphic core complexes -- regional uplift, up to 2regional uplift, up to 2--3 km3 km

widespread volcanism in complex multiple graben rift basinswidespread volcanism in complex multiple graben rift basins

Environments and faciesEnvironments and facies alluvial fan, fluvial, lacustrinealluvial fan, fluvial, lacustrine

VolcanismVolcanism

flood basalts, bimodal basaltflood basalts, bimodal basalt--rhyoliterhyolite--andesite: lavas & pyroclasticsandesite: lavas & pyroclastics tholeiitic, alkaline, calctholeiitic, alkaline, calc--alkaline: lavas & pyroclastics.alkaline: lavas & pyroclastics.

ProvenanceProvenance mixed crustal sourcesmixed crustal sources

contemporaneous volcanic sourcescontemporaneous volcanic sources


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Oceanic Rift BasinsOceanic Rift Basins

Initially narrow (e.g. Red Sea)Initially narrow (e.g. Red Sea)

may evolve into open oceanic basinsmay evolve into open oceanic basins

OriginOrigin narrow continental rifts evolvenarrow continental rifts evolve

breakbreak--upup

oceanic spreading ridgeoceanic spreading ridge oceanic crust in axial basinsoceanic crust in axial basins

continental crust at basin margincontinental crust at basin margin

Environments & faciesEnvironments & facies alluvial fans, fan deltas, shoreline narrow shelf, slope, abyssal plainalluvial fans, fan deltas, shoreline narrow shelf, slope, abyssal plain

VolcanismVolcanism MORB tholeiitic oceanic crustMORB tholeiitic oceanic crust

Lavas, hyaloclastiteLavas, hyaloclastite

ProvenanceProvenance mixed continentalmixed continental

contemporaneous volcanicscontemporaneous volcanics

shelf carbonate, evaporitesshelf carbonate, evaporites

oceanic carbonate, evaporitesoceanic carbonate, evaporites

oceanic pelagic, hemioceanic pelagic, hemi--pelagicpelagic


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Open Ocean PassiveOpen Ocean Passive--MarginMargin

BasinsBasins Evolve from oceanic rift basinsEvolve from oceanic rift basins Become passive margin basins when MORsBecome passive margin basins when MORs -- large, wide oceanlarge, wide ocean

basins.basins.

Half graben system evolves into coastal plainHalf graben system evolves into coastal plain--continental shelf &continental shelf &slopeslope oceanic abyssal plain systemoceanic abyssal plain system

VolcanismVolcanism none expected after breaknone expected after break--upup

perhaps intraplate hot spot volcanismperhaps intraplate hot spot volcanism

Sedimentation & provenanceSedimentation & provenance as for oceanic rift basinas for oceanic rift basin

+ well developed shelf+ well developed shelf--slope seds (slope seds (ss carbonate seds.)carbonate seds.)

TectonicsTectonics postpost--breakbreak--up thermal & later isostatic subsidence of continental marginup thermal & later isostatic subsidence of continental margin

transgressiontransgression


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Convergent Plate MarginConvergent Plate Margin

BasinsBasins


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Continental Margin ArcContinental Margin Arc--SubductionSubduction

Associated Basins

Associated Basins

OriginOrigin oceanic plate being subducted under continentaloceanic plate being subducted under continental

marginmargin

trench, accretionary prism, continental margintrench, accretionary prism, continental marginvolcanic arcvolcanic arc

E.g. Andes, Cascades arcE.g. Andes, Cascades arc

VolcanismVolcanism calccalc--alkaline arc volcanismalkaline arc volcanism

andesites, dacites, rhyolites, rhyodacites, minor basaltsandesites, dacites, rhyolites, rhyodacites, minor basalts

hydrous fluids from subducting lab melt mantle above, & bothhydrous fluids from subducting lab melt mantle above, & boththen melt the base of the crustthen melt the base of the crust

lavas + pyroclasticslavas + pyroclastics


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Associated Basins

Associated Basins Basin types: environments & faciesBasin types: environments & facies

Trench basinTrench basin deep marinedeep marine

turbidites, pelagic seds.turbidites, pelagic seds.

Forearc basinForearc basin perched on "scraped off", imbricate thrust faulted, accretionary prismperched on "scraped off", imbricate thrust faulted, accretionary prism

alluvial fan, fluvial, shoreline shelf, deep turbidite fansalluvial fan, fluvial, shoreline shelf, deep turbidite fans

Back arcBack arc--foreland basinforeland basin lies behind arclies behind arc

at foot of craton directed fold & thrust belt if presentat foot of craton directed fold & thrust belt if present

alluvial fan, fluvial, lakesalluvial fan, fluvial, lakes

IntraIntra--arcarc arc volcanoes often lie in major grabenarc volcanoes often lie in major graben

alluvial fan, fluvial, lakealluvial fan, fluvial, lake


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Associated Basins

Associated Basins

Sediment compositionsSediment compositions

TrenchTrench

metasedimentary debris eroded off accretionary prismmetasedimentary debris eroded off accretionary prism

v. minor volcanic debrisv. minor volcanic debris pelagic sed.pelagic sed.

Forearc basinForearc basin

voluminous volcanic debrisvoluminous volcanic debris

BackBack--arc basinarc basin arc & thrust belt derivedarc & thrust belt derived

mixed volc., metamixed volc., meta--sed., metamorphic, plutonicsed., metamorphic, plutonic

IntraIntra--arc basinsarc basins: lavas, volcanic seds, pyroclastics: lavas, volcanic seds, pyroclastics


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Island ArcIsland Arc--Subduction AssociatedSubduction Associated

BasinsBasins E.g. Marianas, TongaE.g. Marianas, Tonga--Kermadec arcsKermadec arcs

OriginOrigin oceanic plate is subducted under another oceanic plateoceanic plate is subducted under another oceanic plate

trench, accretionary prism, volcanic island arctrench, accretionary prism, volcanic island arc

volcanic arc on oceanic lithospherevolcanic arc on oceanic lithosphere

back arc basin(s) originate by rifting of arc block, development ofback arc basin(s) originate by rifting of arc block, development ofsmall spreading ridgesmall spreading ridge

widening basin; oceanic crustwidening basin; oceanic crust

arc block migrates trenchward as subducting plate "rolls back".arc block migrates trenchward as subducting plate "rolls back".

VolcanismVolcanism island arc tholeiitic volcanicsisland arc tholeiitic volcanics

basalts, basaltic andesitesbasalts, basaltic andesites

back arc basin tholeiitic crustback arc basin tholeiitic crust


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Island ArcIsland Arc--Subduction AssociatedSubduction Associated

BasinsBasins Basin types, environments, facies, provenanceBasin types, environments, facies, provenance

Trench basinTrench basin turbidites, pelagic sedimentsturbidites, pelagic sediments

metasedimentary sed. from accretionary prismmetasedimentary sed. from accretionary prism

arc derived volcanic sedimentarc derived volcanic sediment

ForeFore--arc basinarc basin on accretionary prismon accretionary prism

volcanic seds., carbonatesvolcanic seds., carbonates

turbiditesturbidites

Back arc basinBack arc basin arc derived volcaniclastic turbidite apronarc derived volcaniclastic turbidite apron

pelagic sediments, especially where basin is largepelagic sediments, especially where basin is large

no continental derived sedimentno continental derived sediment

only rare silicic volcanismonly rare silicic volcanism


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Continental Collision Belts & BasinsContinental Collision Belts & Basins

E.g. Himalayan mountain chain, European AlpsE.g. Himalayan mountain chain, European Alps

OriginOrigin long term subduction of oceanic plate under continental margin, will bringlong term subduction of oceanic plate under continental margin, will bring

"passenger" continent into collision with arc host continent."passenger" continent into collision with arc host continent.

oceanic basin closes during collisionoceanic basin closes during collision

subducting continent under thrust oversubducting continent under thrust over--riding continentriding continent uplift, mountain range, double continental crust thicknessuplift, mountain range, double continental crust thickness

VolcanismVolcanism subduction related volcanism stop at collision, when subduction stopsubduction related volcanism stop at collision, when subduction stop

granitoid plutonism may occur due to extremely thickened crustgranitoid plutonism may occur due to extremely thickened crust magmas won't rise because of compressional stress fieldmagmas won't rise because of compressional stress field

Basin types, environments, facies provenanceB

asin types, environments, facies provenance foreland basin at foot of fold & thrust beltforeland basin at foot of fold & thrust belt subject to isostatic subsidencesubject to isostatic subsidence

huge sediment flux off mountain belthuge sediment flux off mountain belt

alluvial fan, braided river, meandering river, lake environments & faciesalluvial fan, braided river, meandering river, lake environments & facies

metasedimentary, met. (include high grade plutonic, reflecting deep crustalmetasedimentary, met. (include high grade plutonic, reflecting deep crustalerosion)erosion)


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Continental StrikeContinental Strike--Slip BasinsSlip Basins

E.g. California borderland basins associated with SanE.g. California borderland basins associated with SanAndreas strikeAndreas strike--slip fault systemslip fault system

OriginOrigin strikestrike--slip along nonslip along non--linear faultslinear faults

opening "holes" or basins at fault jogs or bendsopening "holes" or basins at fault jogs or bends

VolcanismVolcanism usually none, unless "accidental" intraplateusually none, unless "accidental" intraplate

Basin types, environments, facies, provenanceBasin types, environments, facies, provenance

"pull"pull--apart" or strikeapart" or strike--slip basinsslip basins alluvial fans, rivers, lakesalluvial fans, rivers, lakes

alluvial, lacustrine, coal, ?evaporite seds.alluvial, lacustrine, coal, ?evaporite seds.

provenance: whatever is being eroded from exposed crustprovenance: whatever is being eroded from exposed crust


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Stable Continental Interior BasinsStable Continental Interior Basins

E.g. Lake Eyre BasinE.g. Lake Eyre Basin

Intracratonic (= within stable continentalIntracratonic (= within stable continental

crustal mass)crustal mass) Long term stabilityLong term stability

Flat topographyFlat topography

River, desert, lake environments & faciesRiver, desert, lake environments & facies Mature basement derived sed.Mature basement derived sed. ss

evaporitesevaporites

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17156896 Sedimentary Basins Petroleum Geology