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

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

15. 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)

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

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

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

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

23. Methane Hydrates

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

29. 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)

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

38. The rise of mammals

40. Miocene Eocene

44. The evolution of whales

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

50. 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.