HR: 17:00h
AN: GP44A-05 INVITED     [Abstracts]
TI: Towards a Circum-Antarctic Holocene Paleointensity Record
AU: * Brachfeld, S
EM: brachfelds@mail.montclair.edu
AF: Department of Earth and Environmental Studies, Montclair State University, 1 Normal Avenue, Montclair, NJ 07043 United States
AU: Kissel, C
EM: Catherine.Kissel@lsce.cnrs-gif.fr
AF: Laboratoire des Sciences du Climat et de l'Environnement, Unité Mixte CEA-CNRS Avenue de la Terrasse, Gif-sury-Yvette, 91198 France
AU: Laj, C
EM: Carlo.Laj@lsce.cnrs-gif.fr
AF: Laboratoire des Sciences du Climat et de l'Environnement, Unité Mixte CEA-CNRS Avenue de la Terrasse, Gif-sury-Yvette, 91198 France
AU: Willmott, V
EM: vwillmot@hamilton.edu
AF: Hamilton College, Department of Geology, 198 College Hill Road, Clinton, NY 13323 United States
AB: New Holocene geomagnetic paleointensity records have been constructed from the Western Antarctic Peninsula (WAP), Eastern Antarctic Peninsula (EAP), and from the East Antarctic Margin (EAM). The goal of this work is to develop Antarctic paleointensity reference curves for correlation and dating of Antarctic continental shelf sediments. Sediment sequences deposited in fjords and inner shelf basins contain Holocene sections of 3-meters to more than 20-meters, recording the last deglaciation, the paleohistory of ice shelves, and shifting paleoceanographic conditions. However, these records suffer from a lack biogenic calcite for radiocarbon dating. Diatomaceous mud contains sufficient acid insoluble organic matter (aiom) for radiocarbon dating and hence an independent chronology. However, laminated oozes yield shallow inclinations, hence the remanence vector is suspect. Bioturbated diatomaceous mud and diatom-poor muds yield excellent directional records and satisfy the criteria for magnetic uniformity, however the organic content is low and aiom dates can be problematic. Our paleointensity records show the broad pattern of higher intensity during the late Holocene, and lower intensity during the early to middle Holocene, similar to the sinusoidal intensity pattern seen in global absolute and relative paleointensity stacks. Several of the records contain 3 to 4 late Holocene peaks with 1000-year wavelengths that are similar in amplitude and duration to features seen in northern hemisphere lacustrine and marine records. Here we evaluate the local versus regional character of the Antarctic paleointensity records, and the consistency of aiom-dated versus paleointensity-tuned chronologies.
DE: 1521 Paleointensity
DE: 1522 Paleomagnetic secular variation
DE: 1540 Rock and mineral magnetism
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005