HR: 0800h
AN: PP51E-1363    [Abstracts]
TI: Ice-rafted Detritus, Diatoms and the Climate of the Atlantic Sector of the Southern Ocean During the Last 15,000 Years
AU: * Nielsen, S H
EM: snielsen@geology.ufl.edu
AF: Department of Geological Sciences, University of Florida 241 Williamson Hall, Gainesville, FL 32611 United States
AU: Koc, N
EM: nalan@npolar.no
AF: Norwegian Polar Institute, The Polar Environmental Center, Tromsoe, N-9296 Norway
AU: Crosta, X
EM: x.crosta@epoc.u-bordeaux1.fr
AF: UMR-CNRS 5808 EPOC, Avenue des Facult‚s Universit‚ de Bordeaux I, Talence Cedex, 33405 France
AU: Hodell, D A
EM: dhodell@geology.ufl.edu
AF: Department of Geological Sciences, University of Florida 241 Williamson Hall, Gainesville, FL 32611 United States
AU: Kanfoush, S L
EM: skanfoush@utica.edu
AF: Department of Geology, Utica College 1600 Burrstone Road, Utica, NY 13502 United States
AB: The late deglaciation and Holocene of the Atlantic sector of the Southern Ocean appear to be periods of relatively stable climatic conditions, compared to the last glacial period. This smoothly changing climate seems only to have been interrupted by abrupt events during the Antarctic Cold Reversal and during the middle Holocene Neoglacial cooling. This is apparent in ice-core records, as well as in records of Ice Rafted Detritus (IRD) from deep-ocean sediment cores. However, IRD deposition can increase through increased ice-berg production during warming as well as increased ice-berg survivability during cold periods. As paleoclimate records differ on the timing and magnitude of the cold periods, the climate in periods of increased IRD deposition needs scrutinizing. Two decadal-resolution records of diatom-based sea-surface temperature and annual sea-ice duration from the region of the Antarctic Polar Front show very different climate changes in periods of increased IRD deposition. Together with oxygen isotope records from foraminifera and diatoms, as well as records of dust deposition from Antarctic ice-cores, they illustrate how IRD deposition may be only partly dependent on the marine climate. Conditions at the ice-berg producing glacial fronts may be equally important. Also, the records show that the Antarctic Polar Front is not just a climatic barrier for atmospheric circulation, but also controls the melting pattern for ice-bergs transported into the open ocean.
DE: 9310 Antarctica
DE: 4267 Paleoceanography
DE: 4558 Sediment transport
DE: 3022 Marine sediments--processes and transport
DE: 3030 Micropaleontology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting