georefid:2007-117261SEDIS 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/G23874A.12007-01-01publicationgeorefid:2007-117261doi:10.1130/G23874A.1Forster, AstridRoyal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, Den Burg, NetherlandsauthorSchouten, StefanauthorBaas, MarianneauthorSinninghe Damste, Jaap S.authorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)35 (10)919-922Paleoclimate records of geologic time periods characterized by extreme global warmth such as the mid-Cretaceous are important for a better understanding of the Earth's climate system operating in an exceptionally warm mode. Here we applied an organic geochemical proxy (TEX (sub 86) ) on organic matter-rich Albian-Santonian sediments, recovered from Ocean Drilling Program Leg 207 Sites 1258 and 1259 on Demerara Rise, to reconstruct sea surface temperatures (SSTs) in the western equatorial Atlantic. Preceded by a stepwise Cenomanian warming trend ( approximately 31-35 degrees C), the onset of the Cretaceous thermal maximum coincided here with the Cenomanian-Turonian boundary event. Once established, this extreme warm climate regime, characterized by averaged tropical SSTs close to 35 degrees C, lasted up to the Turonian-Coniacian transition. Two pronounced cooler intervals ( approximately 2-3 degrees C) interrupt this otherwise remarkably stable record, providing the first delta (super 18) O independent evidence for middle Turonian cooling that previously has been attributed to glacioeustatic sea-level lowering. Coniacian SSTs decline stepwise, reaching a minimum in the Santonian ( approximately 32-33 degrees C), where cooling is most pronounced, presumably concomitant with the first progressive opening of a deep-water passage through the equatorial Atlantic gateway.completedStratigraphyAlbianAtlantic OceanC-13/C-12carbonclimate changecorescorrelationCretaceousDemerara RiseEquatorial Atlanticgatewaysgeochemistryisotope ratiosisotopesLeg 207Lower Cretaceousmarine environmentmarine sedimentsMesozoicMiddle CretaceousNorth AtlanticNorthwest AtlanticOcean Drilling ProgramODP Site 1258ODP Site 1259organic compoundspaleo-oceanographypaleoclimatologypaleogeographypaleotemperatureSantoniansea-surface temperaturesedimentsSenonianstable isotopestropical environmentUpper CretaceousWest Atlanticurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1258urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1259urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignEnglishgeoscientificInformation-54.4400-54.12009.18009.2600With GSA Data Repository Item 2007227