georefid:2007-029081SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1130/G23175A.12007-01-01publicationgeorefid:2007-029081doi:10.1130/G23175A.1Pearson, Paul N.Cardiff University, School of Earth, Ocean and Planetary Sciences, Cardiff, United Kingdomauthorvan Dongen, Bart E.University of Bristol, United KingdomauthorNicholas, Christopher J.Trinity College, IrelandauthorPancost, Richard D.Netherlands Institute for Sea Research, NetherlandsauthorSchouten, StefanTanzania Petroleum Development Corporation, TanzaniaauthorSingano, Joyce M.Rutgers University, United StatesauthorWade, Bridget S.authorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)35 (3)211-214Earth's climate cooled from a period of extreme warmth in the early Eocene Epoch (ca. 50 Ma) to the early Oligocene (ca. 33 Ma), when a large ice cap first appeared on Antarctica. Evidence from the planktonic foraminifer oxygen isotope record in deep-sea cores has suggested that tropical sea-surface temperatures declined by 5-10 degrees over this interval, eventually becoming much cooler than modern temperatures. Here we present paleotemperature estimates from foraminifer isotopes and the membrane lipids of marine Crenarcheota from new drill cores in Tanzania that indicate a warm and generally stable tropical climate over this period. We reinterpret the previously published isotope records in the light of comparative textural analysis of the deep-sea foraminifer shells, which shows that in contrast to the Tanzanian material, they have been diagenetically recrystallized. We suggest that increasingly severe alteration of the deep-sea plankton shells through the Eocene produced a diagenetic overprint on their oxygen isotope ratios that imparts the false appearance of a tropical sea-surface cooling trend. This implies that the long-term Eocene climatic cooling trend occurred mainly at the poles and had little effect at lower latitudes.completedStratigraphyAfricaalterationC-13/C-12carbonCenozoicclimate changecoolingCrenarcheotadeep-sea environmentdiagenesisEast AfricaEoceneerrorsfatty acidsForaminiferageochemistryInvertebrataisotope ratiosisotopesKilwa GroupLeg 143Leg 198lipidsmarine environmentmicrofossilsO-18/O-16Ocean Drilling ProgramODP Site 1209ODP Site 865organic acidsorganic compoundsoxygenPacific OceanPaleocenepaleoclimatologypaleoecologyPaleogenepaleolatitudepaleomagnetismpaleotemperatureplanktonic taxapreservationProtistasea-surface temperatureshellsstabilitystable isotopesTanzaniaTertiarytexturestropical environmenturn:org.iodp:exp:143urnlargerWorkCitationcampaignurn:org.iodp:exp:198urnlargerWorkCitationcampaignurn:org.iodp:exp:198:site:1209urnlargerWorkCitationstudyurn:org.iodp:exp:198urnlargerWorkCitationcampaignurn:org.iodp:exp:143:site:865urnlargerWorkCitationstudyurn:org.iodp:exp:143urnlargerWorkCitationcampaignEnglishgeoscientificInformation-179.3321158.310018.262432.4000With GSA Data Repository Item 2007047