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The Age of the Earth
bull Prior to the 19th century accepted age of Earth based on religious beliefs ndash ~6000 years for Western culture (Biblical)
ndash Old beyond comprehension (ChineseHindu)
bull James Hutton theldquofather of geologyrdquo realized geologic processes require vast amounts of time
bull Charles Lyell popularized Huttonrsquos concepts in book Principles of Geologyndash Uniformitarianismactualism same processes operating in past are
operating at present - ldquoThe present is the key to the pastrdquo
History of Early Geology
Catastrophism (James Ussher mid 1600s) - He interpreted the Bible to determine that the Earth was created at 4004 BC This was generally accepted by both the scientific and religious communities Subsequent workers then developed the notion of catastrophism which held that the Earthrsquos landforms were formed over very short periods of time
Uniformitarianism (James Hutton late 1700s) - He proposed that the same processes that are at work today were at work in the past Summarized by ldquoThe present is the key to the pastrdquo Hutton not constrained by the notion of a very young planet recognized that time is the critical element to the formation of common geologic structures Uniformitarianism is a basic foundation of modern geology
Lifespan of a human ~ 100 years
Human civilization ~10000 years
Modern humans ~100000 years
Stone tools ~1000000 years
Age of oceanic crust ~100000000 years
Precambrian Explosion ~540000000 years
Oldest Rocks ~38 Billion years
Age of the Earth ~43 Billion years
Age of the Solar System ~46 Billion years
Age of the Universe ~14 Billion years
Geologic Time and Clocks
Relative vs Numerical Age
bull Relative age - the order of events or objects from first (oldest) to last (youngest)ndash Determined by applying simple principles including original
horizontality superposition lateral continuity cross-cutting relationships inclusions unconformities and correlation of rock units and fossils
bull Numerical age - the age of events or objects expressed as a number or numbersndash Determined using radiometric dating (determining how much
radioactive decay of a specific element has occurred since a rock formed or an event occurred)
Absolute Ages
bull Numerical dating - puts absolute values (eg millions of years) on the ages of rocks and geologic time periodsndash Uses radioactive decay of
unstable isotopes
ndash Only possible since radioactivity was discovered in 1896
ndash Radioactive isotopes decay in predictable manner giving a characteristic half-life (time it takes for a given amount of radioactive isotope to be reduced by half)
N = N0 e-kt
Radioactive Decay
Where N is the amount of the radioactive element in the rock
now N0 is the amount originally in the rock e ~ 2718 (natural
logarithm) k is the decay constant of the radioactive
element and t is time
Half-life when NN0 = 05
Absolute (Radiometric) Dating Using radioactive decay of elements to determine the absolute age of rocks This is done using igneous and metamorphic rocks
Absolute Time Radiometric Clocks
Carbon-14 half-life ~ 5730 yearsUsed in anthropology
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
History of Early Geology
Catastrophism (James Ussher mid 1600s) - He interpreted the Bible to determine that the Earth was created at 4004 BC This was generally accepted by both the scientific and religious communities Subsequent workers then developed the notion of catastrophism which held that the Earthrsquos landforms were formed over very short periods of time
Uniformitarianism (James Hutton late 1700s) - He proposed that the same processes that are at work today were at work in the past Summarized by ldquoThe present is the key to the pastrdquo Hutton not constrained by the notion of a very young planet recognized that time is the critical element to the formation of common geologic structures Uniformitarianism is a basic foundation of modern geology
Lifespan of a human ~ 100 years
Human civilization ~10000 years
Modern humans ~100000 years
Stone tools ~1000000 years
Age of oceanic crust ~100000000 years
Precambrian Explosion ~540000000 years
Oldest Rocks ~38 Billion years
Age of the Earth ~43 Billion years
Age of the Solar System ~46 Billion years
Age of the Universe ~14 Billion years
Geologic Time and Clocks
Relative vs Numerical Age
bull Relative age - the order of events or objects from first (oldest) to last (youngest)ndash Determined by applying simple principles including original
horizontality superposition lateral continuity cross-cutting relationships inclusions unconformities and correlation of rock units and fossils
bull Numerical age - the age of events or objects expressed as a number or numbersndash Determined using radiometric dating (determining how much
radioactive decay of a specific element has occurred since a rock formed or an event occurred)
Absolute Ages
bull Numerical dating - puts absolute values (eg millions of years) on the ages of rocks and geologic time periodsndash Uses radioactive decay of
unstable isotopes
ndash Only possible since radioactivity was discovered in 1896
ndash Radioactive isotopes decay in predictable manner giving a characteristic half-life (time it takes for a given amount of radioactive isotope to be reduced by half)
N = N0 e-kt
Radioactive Decay
Where N is the amount of the radioactive element in the rock
now N0 is the amount originally in the rock e ~ 2718 (natural
logarithm) k is the decay constant of the radioactive
element and t is time
Half-life when NN0 = 05
Absolute (Radiometric) Dating Using radioactive decay of elements to determine the absolute age of rocks This is done using igneous and metamorphic rocks
Absolute Time Radiometric Clocks
Carbon-14 half-life ~ 5730 yearsUsed in anthropology
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Lifespan of a human ~ 100 years
Human civilization ~10000 years
Modern humans ~100000 years
Stone tools ~1000000 years
Age of oceanic crust ~100000000 years
Precambrian Explosion ~540000000 years
Oldest Rocks ~38 Billion years
Age of the Earth ~43 Billion years
Age of the Solar System ~46 Billion years
Age of the Universe ~14 Billion years
Geologic Time and Clocks
Relative vs Numerical Age
bull Relative age - the order of events or objects from first (oldest) to last (youngest)ndash Determined by applying simple principles including original
horizontality superposition lateral continuity cross-cutting relationships inclusions unconformities and correlation of rock units and fossils
bull Numerical age - the age of events or objects expressed as a number or numbersndash Determined using radiometric dating (determining how much
radioactive decay of a specific element has occurred since a rock formed or an event occurred)
Absolute Ages
bull Numerical dating - puts absolute values (eg millions of years) on the ages of rocks and geologic time periodsndash Uses radioactive decay of
unstable isotopes
ndash Only possible since radioactivity was discovered in 1896
ndash Radioactive isotopes decay in predictable manner giving a characteristic half-life (time it takes for a given amount of radioactive isotope to be reduced by half)
N = N0 e-kt
Radioactive Decay
Where N is the amount of the radioactive element in the rock
now N0 is the amount originally in the rock e ~ 2718 (natural
logarithm) k is the decay constant of the radioactive
element and t is time
Half-life when NN0 = 05
Absolute (Radiometric) Dating Using radioactive decay of elements to determine the absolute age of rocks This is done using igneous and metamorphic rocks
Absolute Time Radiometric Clocks
Carbon-14 half-life ~ 5730 yearsUsed in anthropology
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Relative vs Numerical Age
bull Relative age - the order of events or objects from first (oldest) to last (youngest)ndash Determined by applying simple principles including original
horizontality superposition lateral continuity cross-cutting relationships inclusions unconformities and correlation of rock units and fossils
bull Numerical age - the age of events or objects expressed as a number or numbersndash Determined using radiometric dating (determining how much
radioactive decay of a specific element has occurred since a rock formed or an event occurred)
Absolute Ages
bull Numerical dating - puts absolute values (eg millions of years) on the ages of rocks and geologic time periodsndash Uses radioactive decay of
unstable isotopes
ndash Only possible since radioactivity was discovered in 1896
ndash Radioactive isotopes decay in predictable manner giving a characteristic half-life (time it takes for a given amount of radioactive isotope to be reduced by half)
N = N0 e-kt
Radioactive Decay
Where N is the amount of the radioactive element in the rock
now N0 is the amount originally in the rock e ~ 2718 (natural
logarithm) k is the decay constant of the radioactive
element and t is time
Half-life when NN0 = 05
Absolute (Radiometric) Dating Using radioactive decay of elements to determine the absolute age of rocks This is done using igneous and metamorphic rocks
Absolute Time Radiometric Clocks
Carbon-14 half-life ~ 5730 yearsUsed in anthropology
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Absolute Ages
bull Numerical dating - puts absolute values (eg millions of years) on the ages of rocks and geologic time periodsndash Uses radioactive decay of
unstable isotopes
ndash Only possible since radioactivity was discovered in 1896
ndash Radioactive isotopes decay in predictable manner giving a characteristic half-life (time it takes for a given amount of radioactive isotope to be reduced by half)
N = N0 e-kt
Radioactive Decay
Where N is the amount of the radioactive element in the rock
now N0 is the amount originally in the rock e ~ 2718 (natural
logarithm) k is the decay constant of the radioactive
element and t is time
Half-life when NN0 = 05
Absolute (Radiometric) Dating Using radioactive decay of elements to determine the absolute age of rocks This is done using igneous and metamorphic rocks
Absolute Time Radiometric Clocks
Carbon-14 half-life ~ 5730 yearsUsed in anthropology
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
N = N0 e-kt
Radioactive Decay
Where N is the amount of the radioactive element in the rock
now N0 is the amount originally in the rock e ~ 2718 (natural
logarithm) k is the decay constant of the radioactive
element and t is time
Half-life when NN0 = 05
Absolute (Radiometric) Dating Using radioactive decay of elements to determine the absolute age of rocks This is done using igneous and metamorphic rocks
Absolute Time Radiometric Clocks
Carbon-14 half-life ~ 5730 yearsUsed in anthropology
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Absolute (Radiometric) Dating Using radioactive decay of elements to determine the absolute age of rocks This is done using igneous and metamorphic rocks
Absolute Time Radiometric Clocks
Carbon-14 half-life ~ 5730 yearsUsed in anthropology
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Relative Age Determination
bull Contacts - surfaces separating successive rock layers (beds)
bull Formations - bodies of rock of considerable thickness with recognizable characteristics allowing them to be distinguished from adjacent rock layers
bull Original horizontality - beds of sediment deposited in water are initially formed as horizontal or nearly horizontal layers
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Relative Age Determination
bull Superposition - within an undisturbed sequence of sedimentary or volcanic rocks layers get younger from bottom to top
bull Lateral continuity - original horizontal layer extends laterally until it tapers or thins at its edges
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Which are the youngest rock layers
Which are the youngest rock layers
What is the sequence of formation
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Relative Age Determination
bull Cross-cutting relationships - a disrupted pattern is older than the cause of the disruptionndash Intrusions and faults are younger than the
rocks they cut through
bull Baked contacts - contacts between igneous intrusions and surrounding rocks where surrounding rocks have experienced contact metamorphism
bull Inclusions - fragments embedded in host rock are older than the host rock
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Which are the youngest rock layers
What is the sequence of formation
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Unconformities
bull Unconformity - a surface (or contact) that represents a gap in the geologic record
bull Disconformity - an unconformity in which the contact representing missing rock layers separates beds that are parallel to each other
bull Angular unconformity - an unconformity in which the contact separates overlying younger layers from eroded tilted or folder layers
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Unconformities
bull Nonconformity - an unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rockndash Plutonic and metamorphic rocks
exposed by large amounts of erosion
ndash Typically represents a large gap in the geologic record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Which are the youngest rock
layers
What is the sequence of formation
Where is the unconformity
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
What is the sequence of events
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Correlationbull Correlation - determining the time-equivalency of rock units
ndash Within a region a continent between continents
bull Physical continuityndash Physically tracing a continuous
exposure of a rock unit
ndash Easily done in Grand Canyon
bull Similarity of rock typesndash Assumes similar sequences of rocks
formed at same time
ndash Can be inaccurate if very common rock types are involved
bull Correlation by fossilsndash Fossil species succeed one another through
the layers in a predictable order (faunal succession)
ndash Similar fossil assemblages (groups of different fossil species) used
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
William Smith father of stratigraphy
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Smithrsquos Fossil Assemblages
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Smithrsquos Fossil Assemblages
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
1048708 Lithostratigraphy (correlating rock layers by using rock types)
1048708 Biostratigraphy (correlating rock layers by using fossils)
1048708 Magnetostratigraphy (correlating rock layers by using magnetic reversals)
1048708 Chemostratigraphy (correlating rock layers by using chemical or isotopic methods for correlating eg oxygen isotopes or (iridium spike at end of Cretaceous)
1048708 Chronostratigraphy (correlating rock layers by using absolute andor relative time)
Stratigraphic Methods
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Geologic Time Scale
bull Standard geologic time scale ndash Worldwide relative time scale
ndash Subdivides geologic time based on fossil assemblages
ndash Divided into eons eras periods and epochs
bull Precambrian - vast amount of time prior to the Paleozoic era few fossils preserved
bull Paleozoic era - ldquoold liferdquo
ndash appearance of complex life many fossils
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Geologic Time Scale
bull Mesozoic era - middle lifendash Dinosaurs abundant on land
ndash Period ended by mass extinction
bull Cenozoic era - new lifendash Mammals and birds abundant
ndash We are currently in the Recent (Holocene) Epoch of the Quaternary Period of the Cenozoic Era
ndash Most recent ice ages occurred during the Pleistocene Epoch of the Quaternary Period
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Combining Relative and Numerical Ages
bull Radiometric dating gives numerical time brackets for events with known relative agesndash Individual layers may be dated directly
ndash Radiometric dating of units above and below brackets age of units in between
bull Geologic Time Scalendash Divided into four Eons
bull Hadean Archean Proterozoic Phanerozoic
ndash Precambrian (all time prior to Phanerozoic) represents 87 of geologic time)
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Age of the Earth
bull Numerical dating gives absolute age for Earth of about 456 billion yearsndash Oldest age obtained for
meteorites believed to have been unchanged since the formation of the solar system
ndash Earth and rest of solar system very likely formed at this time
bull Geologic (deep) time is vastndash A long human lifetime (100
years) represents only about 0000002 of geologic time
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Why Study of Historical Geology
bull Survival of the human species may depend on understanding how Earthrsquos subsystems work and interact and exploring the past is our only lsquolaboratoryrsquo for testing hypotheses
bull Knowing what occurred in the past can help us to understand our origins and place in both the Earth and the Universe
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Latest Precambrian Early Paleozoic
Supercontinent Rodinia centered about the south pole breaks apart North America (Laurentia) Baltica and Siberia moved North
Marine Invertebrates
North America arc on the south Baltica and Siberia moved in from the SE
Texas (505-570 Ma) Flat plain remnants of eroded collisional belt (Llano) Shallow marine seas across much of Texas Sandy sediment onshore limestone offshore Trilobites brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Precambrian Stromatolites
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Cyanobacteria ndash green algae
two kinds cyanobacteria from the Bitter Springs chert of central Australia a site dating to the Late Proterozoic about 850 million years old On the left is a colonial chroococcalean form and on the right is the filamentous Palaeolyngbya
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Ediacaran Fauna
Dickinsonia is known from Vendian rocks of south Australia and north Russia It is often considered to be an annelid worm
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Ediacaran Fauna
this unusual disc-shaped form with three-part (triradial) symmetry Named Tribrachidium heraldicum its affinities are still mysterious although distant relationships have been proposed with either the Cnidaria (corals and anemones) or Echinodermata (urchins and seastars)
Kimberella one of the most fascinating Vendian fossils has received a great deal of attention lately It was hypothesized to be a box jellyfish (cubozoan)
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Ediacaran Fauna
Nemiana is one of the simplest of all Vendian fossils and is difficult to interpret It seems to be an impression of a saclike body
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
lsquo The Small Shelliesrsquo
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Burgess Shale
Marrella splendens is a small arthropod somewhat reminiscent of a trilobite
Tuzoia is a bivalved crustacean grossly similar to certain types of modern brine shrimp
specimen is only a small part of Anomalocaris which was a large (up to 60cm or more) arthropod-like predator
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Burgess Shale
Vauxia gracilenta has a branching morphology a sponge
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Burgess Shale
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Trilobites
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Trilobites
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Trace Fossils
Worm trails
Arthropod tracks
Trilobite tracks
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Latest Precambrian Early Paleozoic
Supercontinent Rodinia continues to break apart Pieces move north
-Fish-Glaciation
North America Numerous plates and continental blocks move in from the south and east The Taconic arc collides forming the Taconic orogeny
Texas 438-505 Ma Shallow marine seas across much of inland Texas Warm-water limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Middle Late Paleozoic
Remains of Rodinia (Gondwana) move northward to collide with Laurasia -- creating the super continent Pangaea and the Tethys Ocean
First land-plants
Baltica collides with North America in
the Caledonian-Acadian orogeny
Texas 403-438 Ma Shallow marine seas across much of west Texas - limestone Corals brachiopods
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Middle Late Paleozoic
Most drifting Rodinia blocks assembled into the super continent of Laurussia
Amphibians Fish really get going Ferns
Glaciation
North America Caledonian-Acadian orogeny marks assemblage of Laurussia Gondwana closed in from the south An arc formed along western North America
Texas 360-408 Ma shallow marine sandstones and limestones in west Texas
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Middle Late Paleozoic
Gondwana with a large developing glacier nears southern Laurussia
Fern-forests
North America The Antler arc collides with western North America creating the Antler orogeny
Texas 320-360 Ma shallow marine seas inland Shales and limestones
httpvishnuglgnauedurcbglobaltexthtml
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
httpvishnuglgnauedurcbglobaltexthtml
Middle Late Paleozoic
Rodinia blocks of Laurussia and Siberia collide to form Laurasia
Reptiles
North America Gondwana collides from the south The resulting Appalachian Ouachita Marathon Ural Variscan and Hercynian orogenies formed some of the largest mountains of all time The Ancestral Rockies form
Texas 286-320 Ma Ouachita Mountains Collision formed inland basins filled by seas Limestone sandstone shale
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Latest Paleozoic Early Mesozoic
The supercontinent Pangeae dominates the Permian Earth lying across the equator
Extinctions Trilobites go away
North America A new arc approaches western North America A new spreading center forms as Cimmeria rifts from Gondwana and opens the Tethyian Ocean
The western fringe of Pangaea lay along the eastern margin of the Pacific ring of firerdquo subduction zone
Texas 245-286 Ma Shallow marine inland of mountains Reefs Evaporites Red shales
httpvishnuglgnauedurcbglobaltexthtml
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Latest Paleozoic Early Mesozoic
Mammals
North America Arc collision along western edge forms the Sonoman orogeny
As the Tethys Ocean expands Cimmeria (Turkey Iran and Afghanistan) movenorthward towards Laurasia
Texas 208-245 Ma shales and sandstones in NW Start opening the GOM - red sandstone shale
evaporites
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Middle Mesozoic
Pangaea rotates different components at different rates in different directions -- rifts form
Birds
North America Southern North Atlantic Ocean opens continuing west into the Gulf of Mexico
The Cordilleran arc develops along Pacific margin
Arc forms on western side Nevadan orogeny begins Cimmeria begins collision with Laurasia - Cimmerian orogeny
Texas 144-208 Ma Change in sediment direction Shallow water deposition evaporites in GOM
httpvishnuglgnauedurcbglobaltexthtml
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Middle Mesozoic
The Atlantic continues to expand as Pangaea breaks up
The Cimmerian orogeny continues
North America Arcs and micro continents slam into western region Laramide orogeny in Rockies
Texas 66-144 Ma Influx of sediment from Rockies Shallow Cretaceous sea way across Texas Shallow liestones shales
httpvishnuglgnauedurcbglobaltexthtml
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Late Cretaceous Present
Rifts separate Africa and South America and then India Australia Antarctica North America rifts from Europe
Old Gondwana lands(Africa India Australia) move north toward Eurasia closing the Tethys Ocean and forming the Alpine-Himalayan mountains
The Atlantic lengthens widens the Sevier orogeny continues and the Caribbean arc forms
Texas 65-144 Ma continuing shallow limestone and shale deposition to the southeast (from Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Paleocene Eocene
Himalayan Orogeny Alps and Pyrenees form
The modern patterns of Planet Earth appear
Atlantic continues to open Rocky Mountains grow
Texas 65 - 35 Ma shale and sandstone in southeast region prograde shoreline (from the Rockies) Volcanic activity in Panhandle
httpvishnuglgnauedurcbglobaltexthtml
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Oligocene and Miocene
Orogeny continues inthe Mediterranean region and India nears its junction with southern Asia
Antarctica isolated
Southwestern North America intercepts the East Pacific Rise and a great extensional event the Basin and Range orogeny begins
Texas 35-5 Ma continued sandstoneshale deposition and progradation of shoreline (erosion of Rockies)
httpvishnuglgnauedurcbglobaltexthtml
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Present
Note Best data set available
httpvishnuglgnauedurcbglobaltexthtml
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull Fossils are the remains or traces of prehistoric organismsndash Any evidence of past life
bull Most common in sedimentary rocksndash and in some accumulations of pyroclastic materials especially ash
bull They are extremely useful for determining relative ages of stratandash geologists also use them to ascertain environments of deposition
bull Fossils provide some of the evidence for organic evolutionndash many fossils are of organisms now extinct
Fossils
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull Remains of organisms are called body fossilsndash mostly durable skeletal elements such as bones teeth and shells
How do Fossils Form
ndash rarely we might find entire animals preserved by freezing or mummification
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull Indications of organic activity including tracks trails burrows and nests are called trace fossils
bull A coprolite is a type of trace fossil consisting of fossilized feces that may provide information about the size and diet of the animal that produced it
Trace Fossils
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull A land-dwelling beaver Paleocastor made this spiral burrow in Nebraska
Trace Fossils
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull Fossilized feces (coprolite) of a carnivorous mammalndash specimen measures about 5 cm long and contains small
fragments of bones
Trace Fossils
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull The most favorable conditions for preservation of body fossils occurs when the organismndash possesses a durable skeleton of some kind ndash and lives in an area where burial is likely
bull Body fossils may be preserved as ndash unaltered remains meaning they retain their original composition and
structureby freezing mummification in amber in tar ndash altered remains with some change in composition or structure by being
permineralized recrystallized replaced carbonized
Body Fossil Formation
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull Insects in amber
Unaltered Remains
bull Preservation in tar
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Unaltered Remains
bull 40000-year-old frozen baby mammoth found in Siberia in 1971ndash hair around
the feet is still visible
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull Petrified tree stump in Florissant Fossil Beds National Monument Colorado
Altered Remains
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
Carbon film of a palm frond
Altered Remains
Carbon film of an insect
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
bull The fossil record is the record of ancient life preserved as fossils in rocks
bull The fossil record is very incomplete because ofndash bacterial decay
ndash physical processes
ndash scavenging
ndash metamorphism
bull In spite of this fossils are quite common
Fossil Record
