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The Cenozoic Era

The Cenozoic Era. Ma. 1.8. 5.0. 23.7. 33.5. 54.5. 66.4. Major themes of the Cenozoic. Earth overall climatic cooling (“greenhouse to icehouse”) changes in ocean circulation Pangea breakup continues but slows changes in position of land and sea changes in oceanic nutrient levels Life

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The Cenozoic Era

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  1. The Cenozoic Era Ma 1.8 5.0 23.7 33.5 54.5 66.4

  2. Major themes of the Cenozoic • Earth • overall climatic cooling (“greenhouse to icehouse”) • changes in ocean circulation • Pangea breakup continues but slows • changes in position of land and sea • changes in oceanic nutrient levels • Life • diversification and dominance of mammals • dominance of angiosperms • continuation of the Mesozoic Marine Revolution

  3. The Earth in the Cenozoic • Changes in position of land and sea • destruction of Tethys • effects on climate • effects on ocean circulation • land bridges • Changes in ocean circulation • cooling  more vigorous circulation • continental position  new current patterns • Overall climatic cooling • continental position  S. Hemisph. glaciation

  4. The Deep Sea Drilling / Ocean Drilling Project (DSDP/ODP) JOIDES Resolution Glomar Challenger

  5. Oxygen isotope paleothermometry • O isotope fractionation is temperature-dependent (warmer temps  more 16O, less 18O) • expressed as ppt relative to PDB (Pee Dee Belemnite) • need to correct for ice volume (more glacial ice  SW enriched in 18O)

  6. Oxygen isotope paleothermometry 18O negative = warmer 18O positive = cooler

  7. Major climate events of the Cenozoic • Late Paleocene Thermal Maximum (LPTM) • Eocene-Oligocene cooling / Antarctic glaciation • Miocene cooling • Pleistocene glaciation

  8. The carbon isotopic excursion at the P-E boundary

  9. Possible cause(s) for the LPTM more hydrothermal activity  more CO2  warming  release of methane clathrates  more CO2  warming

  10. Methane Hydrates

  11. Major climate events of the Cenozoic • Late Paleocene Thermal Maximum (LPTM) • Eocene-Oligocene cooling / Antarctic glaciation • Miocene cooling • Pleistocene glaciation

  12. The breakup of Gondwanaland:the death of Tethys and the formation of the Circumantarctic Current • India collides with southern Asia (ca. 55 Ma) • Australia separates from Antarctica (ca. 58 Ma) • South America separates from Antarctica -- the Drake Passage (33.5-23.5 Ma)

  13. Major climate events of the Cenozoic • Late Paleocene Thermal Maximum (LPTM) • Eocene-Oligocene cooling / Antarctic glaciation • Miocene cooling • Pleistocene glaciation

  14. The rise of mammals

  15. Miocene Eocene

  16. The evolution of whales

  17. http://www.indiana.edu/~ensiweb/images/whal.amb.jpeg

  18. An artist's rendering of Rodhocetus. This mammal lived near the shores of the Tethys Sea, between Asia and the South Asian subcontinent, about 47 million years ago.

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