Events
Cenozoic Cenozoic period
Eocene and Modern
Cenozoic
Half of the present sea floor was formed
since the end of the Cretaceous!
Atlantic and Indian rifting had increased.
East Coast
Florida region
Erosion is still dominant.
Passive margins.
Carbonate sediments accumulated
along Florida.
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Eastern passive margin
GOM
Best record of Cenozoic strata in N.A.
8 transgressions/regressions have been
recorded in the sediment layers.
Transgressions as far north as Illinois!
Gulf Coast/GOM
Tectonics and Erosion in the
Rockies
At the end of the Cretaceous was the
Laramide orogeny. This continued
into the middle Eocene (70-40myr ago).
This orogeny produced intermontane
basins.
Cordillera
Laramide orogeny
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Intermontane basins
Eocene freshwater fossils
from intermontane lakes
- Formed large freshwater lakes in the
middle Eocene.
- Green River Formation
- In some places limestone formed.
- Amazing fossil preservation.
- Oil shales.
- Claron Formation
Green River Formation
Oils shales
Location of oil
shales
Eocene Oil Shale & Coal
Organic rich fine
grained sedimentary
rock that contains
high amounts of
kerogen (a solid mix
of organic
compounds), from
which hydrocarbons
and oil can be
produced.
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Badlands National Park
By the Late Eocene &
Oligocene
Limestones & clays
Yellowstone & Grand Tetons
Volcanic activity increased all along the
Cordillera.
Yellowstone formed.
Grand Tetons began to rise.
In the Oligocene and early Miocene
Oligocene tectonics
Ancestral Cascades erupted vast amounts
of green ash.
Volcanism occurred in central Idaho,
Nevada, Utah and Colorado and Wyoming
about 40myr.
Relative decrease in SL.
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In the Oligocene
San Andreas
Pacific Plate touched the N.A. plate for
the first time.
When this happened the San Andreas
fault began, a transform fault.
This changed the geometry of the
Cordillera.
Trees fossilized in ash
Location
Map
Basin & Range
Colorado Plateau
Columbia Plateau
Oligocene
Amazing fossil preservation!
Florisant, Colorado
In the Miocene
Basin and Range Province begins to
form.
The crust of Nevada is now stretched to
twice Miocene its length!
Another phenomenon The Columbia
River Plateau Basalts.
explained by a hotspot in the mantle
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Why is Nevada stretching?
Miocene tectonics
In the Miocene, the Farallon plate
began to separate into two micro plates
and offset by transform faults.
Basin and Range
Basin & Range Topography
Region was a broad arch.
In Miocene, the arch began to subside
between normal faults.
Lava extruded.
Evaporites formed in grabens
Basin and Range
Colorado Uplift
Late Miocene and Pliocene.
Affected the "4 Corners" area (CO, AZ, UT,
NM).
Entire area was uplifted in one block about
1mile in relief- this is the Colorado Plateau.
Also, oil migrated out of the organic rich
Miocene shale and flowed into all the faults
and folds in California, where it accumulated
and formed the California oil fields.
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Colorado Plateau
Grand Canyon
Columbia Plateau
Subduction zone off the coast of
Oregon and Washington states
Volcanic origin.
Miocene.
Similar to Deccan
Traps.
Generated lavas of
Cascade Range.
Mt. St. Helen, Mt.
Lassen, Mt. Rainier,
Crater Lake.
Mount Saint Helens
Sierra Nevada
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Miocene-Pliocene tectonics
Crater Lake
Mount Mazama
Evolution of Farallon plate
Farallon Plate
Evolution of Hawaii
Emperor-Hawaiian chain began to form
in the Cretaceous.
Notice the "jog" in the chain. This
formed in the Oligocene.
This represents a change in plate
direction, and coincides with the Pacific
Plate hitting N.A!
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Pacific Plate dynamics
Also in the Miocene
Evolution of Drake Passage
Until 23mya South America and
Antarctica were connected via the
Antarctic peninsula.
At this time they began to separate.
Evolution of CPC
Hmm what else?
Greenland was still separating from Europe in
the Paleocene.
Also, the Alpine-Himalayan belt began to
form.
End of Tethys Sea
African rifting began in Oligocene and
continues to this day.
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Formation of Alpine-Himalayan orogenic belt
Recent Mountain chains
Modern N.A. Tectonism
African rifting
Tectonics-Climate connection
Isthmus of Panama formed.
Gulf Stream formed.
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Formation of Gulf Stream
Gulf Stream
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