1. Cenozoic History At only 66 million years long,
the Cenozoic is only 1.4% of all geologic time
or only 20 minutes
on our hypothetical 24-hour clock for geologic time

2. Cenozoic Time Scale In this class we use the term Tertiary Period
rather than Paleogene and Neogene Periods

3. Plate Tectonics Three kinds of margins: Divergent Convergent
Ocean-ocean
Ocean-continent
Continent-continent

4. Divergent margins

5. Ocean-ocean convergent margins

6. Ocean-continent convergent margins

7. Continent-continent convergent margins

8. Covergent, more

9. The Himalayas During the Early Cretaceous,
India broke away from Gondwana
and began moving north,
and oceanic lithosphere was consumed
at a subduction zone
along the southern margin of Asia

10. Before India Collided with Asia
Oceanic lithosphere
subducted beneath southern Tibet
as India approached Asia
northern margin of India
southern margin of Tibet

11. India Collided with Asia
About 40 to 50 million years ago
India collided with Asia,
but because India was to light to subduct,
it thrust under Asia

12. Continued Convergence
Thrusting of Asian rocks
onto the Indian subcontinent
accompanied continued convergence

13. India Moved beneath Asia
Since about 10 million years ago,
India has moved beneath Asia
along the main boundary fault
Shallow marine sedimentary rocks
that were deposited along India’s northern margin
now form the higher parts of the Himalayas

14. The Circum-Pacific Orogenic Belt

15. Evolution of the Andes Mountains
Prior to 200 million years ago,
the west coast of South America
was a passive continental margin
where huge quantities of sediment were deposited

16. Evolution of the Andes Mountains
Orogeny began when this area
became an active continental margin
as South America moved to the west
and collided with oceanic lithosphere

17. Evolution of the Andes Mountains
Deformation, volcanism and plutonism continued

18. The North American Cordillera
is one large segment of the circum-Pacific orogenic belt
extending from Alaska to central Mexico
In the United States it widens to 1200 km
stretching east-west
from the eastern flank of the Rocky Mountains
to the Pacific Ocean

19. Cordillera North American Cordillera and the major provinces
of the United States and Canada

20. Sedimentary Basins in the West
Locations of Proterozoic sedimentary Basins
in the western United States and Canada
Belt Basin
Uinta Basin
Apache Basin

21. Cordilleran Mobile Belt
Antler Orogeny in Devonian

22. Cordillera Evolved
After Laramide deformation, Cordillera continued to evolve
large-scale block-faulting
extensive volcanism
vertical uplift and deep erosion
Basin and Range
During about the first half of the Cenozoic Era, a subduction zone was present
along the entire western margin of the Cordillera,
but now most of it is a transform plate boundary
???

23. Plate Interactions Continue

24. The Laramide Orogeny Third in a series of deformational events
in the Cordillera beginning during the Late Jurassic
Late Cretaceous to Eocene
Differed from the previous orogenies in important ways

25. Laramide orogeny took place as the Farallon plate,
buoyed up by a mantle plume
subducted beneath North America
at a decreasing angle
and igneous activity shifted inland
???

26. Change to Shallow Subduction
By Early Tertiary time,
the westward-moving North American plate
had overridden the part of the Farallon plate,
above the head of the mantle plume
The lithosphere
immediately above this plume
was buoyed up,
accounting for a change
from steep to shallow subduction

27. Igneous Activity Ceased
With nearly horizontal subduction,
igneous activity ceased
and the continental crust
was deformed mostly by vertical uplift

28. Renewed Igneous Activity
Disruption of the oceanic plate
by the mantle plume
marked the onset
of renewed igneous activity

29. Cordilleran Igneous Activity
The vast batholiths in
Idaho
British Columbia
Sierra Nevada of California
were emplaced during the Mesozoic Era
intrusive activity continued into Tertiary

30. Tertiary Volcanism more or less continuous in the Cordillera
varied in intensity, eruptive style, and location
ceased temporarily in the area of the Laramide orogen

31. Columbia River Basalts are remnants of a great volcanic event
an aggregate thickness of about 2500 m
well exposed in the walls of the deep gorges
cut by the Columbia and Snake rivers
Some of the individual flows were truly phenomenal
Roza flow alone covers 40,000 km2 and has been traced about 300 km from its source
~ 20 lava flows of the Columbia River basalts exposed in the canyon of the Grand Ronde River in Washington

32. Cascade Range
Some of the highest mountains in the Cordillera are the Cascades
California, Oregon, Washington, British Columbia
Thousands of volcanic vents are present
dozen large volcanoes
Lassen Peak in California
world's largest lava dome
Related to subduction of the Juan de Fuca plate

33. Basin and Range

34. Basin and Range Province
ranges are bounded by faults symptomatic of spreading
Why spreading here?
Action of San Andreas?

35. Colorado Plateau

36. Colorado Plateau: older source rocks
Paleozoic rocks exposed in the Grand Canyon, Arizona
Mesozoic sedimentary rocks in the Valley of the Gods, Utah

37. Colorado Plateau
Mesozoic sedimentary rocks at Colorado National Monument, Colorado

38. Pacific Coast Before the Eocene,
the entire Pacific Coast was a convergent plate boundary
Farallon plate was consumed at a subduction zone
stretched from Mexico to Alaska

39. Change from Subduction
As the North American Plate
overrode the Pacific–Farallon Ridge,
its margin became transform faults
the San Andreas
and the Queen Charlotte
alternating with subduction zones

40. Extending the San Andreas Fault
Further overriding of the ridge
extended the San Andreas Fault
and diminished the size of the Farallon–Plate remnants
Now only two small remnants
of the Farallon plate exist
the Juan de Fuca and Cocos plates

41. The Continental Interior
A vast area called the Interior Lowlands
the Great Plains
and the Central Lowlands

42. Cenozoic History of the Appalachian Mountains
Deformation in the Appalachians has a long history
began during the Late Proterozoic
during Late Triassic time, the entire region experienced faulting as Pangaea fragmented

43. Reduced to Plains By the end of the Mesozoic
erosion had reduced the mountains to a plain across which streams flowed eastward to the ocean

44. Appalachians in the Tertiary
Streams developed across the plains during the Tertiary

45. Present Appalachian Topography
Although these mountains have a long history
their present topographic expression resulted mainly from Cenozoic uplift and erosion

46. The Southern and Eastern Continental Margins
The Atlantic Coastal Plain and the Gulf Coastal Plain
form a continuous belt
from the Northeastern United States to Texas

47. Coastal Plain Similarities
Both areas have
horizontal or gently seaward-dipping strata
deposited mostly by streams flowing across them
Seaward of the coastal plains
lie the continental shelf, slope and rise,
also areas of notable Mesozoic and Cenozoic deposition

48. Gulf Coast Sedimentation Pattern
The overall Gulf Coast sedimentation pattern
was established during the Jurassic
and persists today
Sediments derived from
Cordillera
western Appalachians
Interior Lowlands
were transported toward the Gulf of Mexico
where they were deposited in terrestrial, transitional, and marine environments

49. Gulf-Coastal-Plain Deposition
Cenozoic Deposition on the Gulf Coastal Plain
Depositional provinces and surface geology
Showing facies changes and seaward thickening
Cross section of Eocene Claiborne Group

50. Reservoirs for Hydrocarbons
Many sedimentary rocks in the Gulf Coastal Plain
are either source rocks
or reservoirs for hydrocarbons