1. Earth Science
Chapter 23.3
Cenozoic Era

2. Cenozoic Paeogeography
Cenozoic Era
1.5% total Earth’s history
Last 66 million years
Humans evolved
Present form in Pleistocene Epoch

3. Periods of Cenozoic Era

4. Cooling trend Warm during the first epoch of Cenozoic Era
As Australia separated form Antarctica
Worldwide climate cooled
Caused by change in ocean currents
After separation Antarctica settled over south pole
Cold currents began to flow around it
Permanent ice cap began to form

5. Miocene warming Miocene Period Climate began to warm again
Ice cap- Antarctica began to melt
Oceans flooded margins of North America
Late Miocene
Ice caps began to freeze again
Set the stage for ice ages

6. Ice Ages Starting in Pliocene through Pleistocene
Ice covered most of Earth’s northern hemisphere
Glaciers formed and receded at least 4 times over North America
glaciers were up to 3 km thick
Covered 1/3 of Earth’s land surfaces
Missouri and Ohio Rivers show ancient glacier paths

7. Cenozoic Mountain Building
Mesozoic uplifting created Rocky Mountains
Erosion of Rocky Mountains began in the Cenozoic
Sediments from erosion settled forming well preserved fossils

8. Subduction in the west
Volcanism on west coast of North America returned
Steep subduction of Farallon Plate beneath the Pacific Northwest
Formed Cascade Mountains
Volcanoes here still active

9. Subduction in the west
Farallon Plate disappeared under what is now California
North American Plate now interacts with the oceanic Pacific Plate
San Andres fault formed
Transform boundary
No subduction in California
No volcanic activity

10. Basin and Range Province
Southwestern US and Mexico
Consists of hundreds of nearly parallel mountains
Mountains formed when stresses in Earth’s crust pulled it apart

11. Continental collisions
Final breakup of Pangaea resulted in separate continents
Africa began to collide with Eurasia (Paleocene)
Created Alps
Narrowed ancien Tethys Ocean
Remnants of this sea are Black, Caspian, Aral and Mediterranean Seas

12. Tectonic forces continue
Opinions on the future of climate varies
Tectonic movement is certain
Some scientist believe that plate movement will eliminate the Atlantic Ocean and create another super continent

13. Cenozoic life
Marine life that survived extinction at the end of Cretaceous period
Clams, sea urchins, sharks
Forests dominated continents
As climate cooled
Grasslands appeared
Rise of grasslands led to diverse new mammal groups
Age of Mammals

14. Ice age mammals As ice ages began- climate cooled New animals evolved
Wooly mammoth and saber toothed cat
Homo sapiens- modern humans

15. Humans Defining characteristics First fossil remains found in Africa
Standing upright
Bipedal
First fossil remains found in Africa
195,000 years old

16. Migrations Human migration influenced by ice age of late Pleistocene
Theories state that land bridge across Bering Straight aided in migration of humans to North America