HR: 16:55h
AN: PP54A-04    [Abstracts]
TI: Two Highly-Resolved Geochemical Records of Holocene Variability: A Comparison Between West and East Antarctica
AU: * Kryc, K A
EM: kkryc@joiscience.org
AF: Stanford University, Dept. of Geological and Environmental Sciences, Stanford, CA 94305 United States
AU: Murray, R W
AF: Boston University, Dept. of Earth Sciences, Boston, MA 02215 United States
AU: Dunbar, R B
AF: Stanford University, Dept. of Geological and Environmental Sciences, Stanford, CA 94305 United States
AU: Roehl, U
AF: Bremen University, Dept. of Geosciences, Bremen, 28334 Germany
AU: Leventer, A
AF: Colgate University, Dept. of Geology, Hamilton, NY 13346 United States
AU: Manley, P L
AF: Middlebury College, Dept. of Geology, Middlebury, VT 05753 United States
AB: Based on results from ODP Site 1098 in the Palmer Deep, we have a highly resolved record of West Antarctic Holocene climate evolution as traced by terrigenous provenance and accumulation, nutrient utilization, and surface and export production. To date, there are few comparable records from East Antarctica despite its critical role in deep ocean circulation. Here we compare results from a 25 m core recovered from Iceberg Alley on the MacRobertson Shelf of East Antarctica with the results from the Palmer Deep (PD), West Antarctica. Both cores are characterized by laminated diatomaceous muds comprising a two-component system of biogenic opal and terrigenous material. Both of these sedimentary sequences span the Holocene and capture the termination of the deglaciation event at 10kyr. The geochemical parameters we used include XRF scanned and discrete ICP-ES major and trace element analyses, biogenic opal, and carbon and nitrogen isotopes. The PD geochemical records are strongly delineated between the Holocene Climate Optimum (HCO) and the Neoglacial. Both surface and export production are elevated through the HCO, which is indicative if a warmer period. Additionally, the terrigenous provenance record of Al/Ti shows that the source of sediment during the HCO was different than during the Neoglacial. This is likely the result of water mass reorganization as a function of Westerly wind strength. The major events seen in the PD record have also been observed worldwide. In contrast, the Iceberg Alley record does not show a difference between the HCO and the Neoglacial. Rather, there are high-frequency changes that appear to vary over an unchanged average throughout the Holocene. There is, however, a large change in both the absolute values and the amplitude of the signal at 10kyr that signifies the termination of the deglaciation event. Why the Iceberg Alley records do not reflect the same structure exhibited in the PD records remains to be determined. As a first approximation, it appears that the climatic conditions differed between these two sites during the Holocene.
DE: 4825 Geochemistry
DE: 4835 Inorganic marine chemistry
DE: 3670 Minor and trace element composition
DE: 4215 Climate and interannual variability (3309)
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting