georefid:2005-062938SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1126/science.1110063<gco:CharacterString>Marked decline in atmospheric carbon dioxide concentrations during the Paleogene</gco:CharacterString>2005-01-01publicationgeorefid:2005-062938doi:10.1126/science.1110063Pagani, MarkYale University, Department of Geology and Geophysics, New Haven, CT, United StatesauthorZachos, James C.University of California at Santa Cruz, United StatesauthorFreeman, Katherine H.Pennsylvania State University, United StatesauthorTipple, BrettauthorBohaty, StevenauthorAmerican Association for the Advancement of Science, Washington, DC, United StatespublisherdocumentDigitalScience309 (5734)600-603The relation between the partial pressure of atmospheric carbon dioxide (pCO (sub 2) ) and Paleogene climate is poorly resolved. We used stable carbon isotopic values of di-unsaturated alkenones extracted from deep sea cores to reconstruct pCO (sub 2) from the middle Eocene to the late Oligocene ( approximately 45 to 25 million years ago). Our results demonstrate that pCO (sub 2) 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 pCO (sub 2) likely allowed for a critical expansion of ice sheets on Antarctica and promoted conditions that forced the onset of terrestrial C (sub 4) photosynthesis.completedStratigraphyalgaealkenonesatmosphereC-13/C-12carboncarbon dioxideCenozoicclimate changeCoccolithophoraceaeconcentrationcorescorrelationEoceneisotope ratiosisotopesketoneslower OligocenemicrofossilsOcean Drilling Programocean floorsOligoceneorganic compoundspaleoclimatologyPaleogenePlantaereconstructionstable isotopesTertiaryupper Eoceneworld oceanEnglishgeoscientificInformationapplication/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://www.sciencemag.org/content/309/5734/600.full.pdfdownload