georefid:2005-007269SEDIS 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=2005-0072692001-01-01publicationgeorefid:2005-007269isbn:0-493-41613-7Joseph, Leah HelenauthordocumentHardcopy205 pp.0-493-41613-7The climatic evolution of Antarctica and its association with the surrounding oceanic circulation are determined using sediment parameters in cores from around Antarctica. These measures include terrigenous flux rates and grain size analysis, bulk magnetic susceptibility values, and magnetic fabrics, measured in samples obtained from Ocean Drilling Program cores that surround Antarctica. Samples extend through the latest Cretaceous and span the time period from before ice formation occurred on Antarctica in the Cretaceous through the onset of modern conditions. Sites analyzed include the Maud Rise in the southern Atlantic Ocean, Kerguelen Plateau in the southern Indian Ocean, and Rekohu Drift in the southwestern Pacific Ocean. Antarctic climate between Late Cretaceous to middle Eocene oscillated between wet and dry periods. The middle Eocene to middle Oligocene period encompassed the first episode of major ice growth on Antarctica. This time period is representative of the evolution of the proto-Antarctic Circumpolar Current (ACC), the opening of the Tasman seaway, and subsequent thermal isolation of Antarctica; the Drake Passage opened to allow at least surface circulation by approximately 32 Ma. The ACC and thermohaline circulation established their present configuration by approximately 23 Ma, resulting in scouring and/or large sediment accumulations by the Pacific Deep Western Boundary Current. Fluctuations related to the intensity of bottom water formation, reflecting Antarctic climate, are recorded during this time, including major growth of the East Antarctic Ice Sheet between 14-11 Ma and the initial formation of the West Antarctic Ice Sheet at approximately 10 Ma. The East Antarctic Ice Sheet exhibited fluctuations from at least 6.4 Ma until approximately 4 Ma. Significantly, the stable cold-based ice sheet becomes established after 4 Ma, during a period of global warmth. (Mod. auth. abstr.)completedStratigraphyAntarctic Circumpolar CurrentAntarctic ice sheetAntarcticaCenozoicclimate changecontrolscoresCretaceousdeep-sea environmentDrake PassageEast Antarctic ice sheetfabricglobalgrain sizeKerguelen Plateaumagnetic susceptibilitymarine environmentMaud RiseMesozoicocean circulationOcean Drilling Programoscillationspaleo-oceanographypaleoatmospherepaleoclimatologypropertiesRekohu DriftsedimentsSouthern Oceanthermohaline circulationUpper CretaceousWeddell SeaWest Antarctic ice sheetEnglishgeoscientificInformation-180.0000180.0000-90.0000-45.0000AntarcticaDrake PassageKerguelen PlateauMaud Rise