Chapter 23 The Paleozoic Mesozoic Cenozoic Eras The
- Slides: 8
Chapter 23 The Paleozoic, Mesozoic, & Cenozoic Eras
The Paleozoic Era Paleozoic Paleogeography Defined by: Breakup of Rodenia Evolution of Multicellular Life Passive margins Sea Level Changes in the Rock Record Shoreline Deposition Transgression Regression Evaporites Mineral deposits Impermeability Glaciation
The Paleozoic Era Mountain Building Laurentia deformed – pg. 651 & 652. Ouachita Orogeny Alleghenian Orogeny Paleozoic Life Cambrian Explosion Nearly every major marine group of today appeared during this time. Lots of Fossils! Ordovician Extinction More than half of marine life. Due to glacial regression.
The Paleozoic Era Paleozoic Life (continued…) Devonian Extinction More than half of marine life, creatures were more advanced. Due to glacial regression. Terrestrial Plants Coal Deposits Permian Changes Largest mass extinction in Earth’s History. 95% of marine life. 65% of amphibians 33% of Insects Caused by glacial regression, volcanism, and meteorite impact.
The Mesozoic Era Mesozoic Paleogeography Defined by: Dinosaurs dominated! All went extinct to close this era. New organisms filled niches, left by extinction. Breakup of Pangaea Due to convection currents. Seaways As the continents split, mid-ocean rift systems developed. Widening seaways, became oceans. Changing Sea Level Mainly it rose due to increased temperatures and the mid-ocean ridge system.
The Mesozoic Era Mountain Building Cordillera – means “mountain range” in Spanish! Eat your heart out Mrs. Lehman! Three Phases of Cordillera Orogeny – Pg. 657. Mesozoic Life Phytoplankton flourish in the warm, shallow seas. Plant Life Conifers and Flowering plants develop. Terrestrial Animals Age of the Reptiles. Mammals appear late. Mass Extinction 50% of Marine life extinct. 56% of Land life extinct… including dinosaurs.
The Cenozoic Era Cenozoic Paleogeography Defined by: The last 66 million years Scientists have more knowledge of this era than any other. Cooling trend Due to a change in ocean currents, as Antarctica moved toward the South Pole. Miocene warming Ice caps melted, but froze again at the poles, setting up ice ages. Ice Ages During their peak, a third of Earth’s Surface was covered in ice. 3 km thick in some places.
The Cenozoic Era Cenozoic Mountain Building – Read pgs. 663 & 664. Subduction in the West Basin & Range Province Continental Collisions Tectonic Forces continue… Cenozoic Life Age of the Mammals Humans appear in the fossil record, in Africa about 195, 000 years ago.