| Title | Marked decline in atmospheric carbon dioxide concentrations during the Paleogene |
| Author | Pagani, M.; Zachos, J.C.; Freeman, K.H.; Tipple, B.; Bohaty, S. |
| Author Affil | Pagani, M., Yale University, Department of Geology and Geophysics, New Haven, CT. Other: University of California at Santa Cruz; Pennsylvania State University |
| Source | Science, 309(5734), p.600-603, . Publisher: American Association for the Advancement of Science, Washington, DC, United States. ISSN: 0036- 8075 |
| Publication Date | July 22, 2005 |
| Notes | In English. 63 refs. GeoRef Acc. No: 288103. CRREL Acc. No: 63000720 |
| Index Terms | algae; carbon isotopes; climatic change; correlation; isotopes; ocean bottom; paleoclimatology; Ocean Drilling Program; alkenones; atmosphere; C-13/C-12; carbon; carbon dioxide; Cenozoic; climate change; Coccolithophoraceae; concentration; cores; Eocene; isotope ratios; ketones; lower Oligocene; microfossils; ocean floors; Oligocene; organic compounds; Paleogene; Plantae; reconstruction; stable isotopes; Tertiary; upper Eocene; world ocean |
| Abstract | The relation between the partial pressure of atmospheric carbon dioxide (pCO2) and Paleogene climate is poorly resolved. We used stable carbon isotopic values of di- unsaturated alkenones extracted from deep sea cores to reconstruct pCO2 from the middle Eocene to the late Oligocene (~45 to 25 million years ago). Our results demonstrate that pCO2 ranged between 1000 to 1500 parts per million by volume in the middle to late Eocene, then decreased in several steps during the Oligocene, and reached modern levels by the latest Oligocene. The fall in pCO2 likely allowed for a critical expansion of ice sheets on Antarctica and promoted conditions that forced the onset of terrestrial C4 photosynthesis. |
| URL | http://hdl.handle.net/10.1126/science.1110063 |
| Publication Type | journal article |
| Record ID | 85030 |