HR: 16:30h
AN: GP44A-03    [Abstracts]
TI: High Resolution Holocene Paleomagnetic Secular Variation Records From the Eastern and Western Canadian Arctic
AU: * St-Onge, G
EM: guillaume_st-onge@uqar.qc.ca
AF: ISMER, 310, allee des Ursulines, Rimouski, QC G5L 3A1 Canada
AU: Stoner, J
EM: jstoner@coas.oregonstate.edu
AF: COAS, Oregon State University 104 COAS Administration Building, Corvallis, OR 97331-5503 United States
AU: Rochon, A
EM: andre_rochon@uqar.qc.ca
AF: ISMER, 310, allee des Ursulines, Rimouski, QC G5L 3A1 Canada
AU: Channell, J E
EM: jetc@geology.ufl.edu
AF: Department of Geological Sciences, University of Florida PO Box 112120 241 Williamson Hall, Gainesville, FL 32611 United States
AB: Several marine piston cores were collected in the summer 2004 on board the icebreaker CCGS Amundsen in the Mackenzie Shelf and Baffin Bay areas as part of the CASES (Canadian Arctic Shelf Exchange Study) and ArcticNet programs in order to determine Holocene geomagnetic field dynamics in the Canadian Arctic. Here we will present u-channel paleomagnetic data and preliminary AMS-¹⁴C results obtained from three Holocene piston cores collected in high sediment accumulation areas (~1 m/kyr) in the Beaufort Sea (core 803: lat. 70°37.976'N, long. 135°52.815'W), Amundsen Gulf (core 250: lat. 71°27.079'N, long. 125°23.562'W) and Baffin Bay (core 009: 74°11.2'N, long. 81°11.7'W). The natural remanent magnetization (NRM) of the u-channel samples was studied by progressive alternating field demagnetisation indicating that the sediments of each core are characterized by a strong (~10^-2 A/m), stable, well-defined, single component magnetization with maximum angular deviation (MAD) values generally lower than 2° for cores 803 and 009 and below 4° for core 250. In addition, concentration dependent parameters such as ARM, IRM and magnetic susceptibility vary by less that one order of magnitude, whereas pseudo S ratios are close to 1, suggesting a high proportion of low coercivity minerals such as magnetite. Aside from the base and top of core 250, where component magnetizations are shallow and poorly defined, component inclinations of each core fluctuate around the expected geocentric axial dipole (GAD) inclination (~ 80°) for the latitude of the sampling sites, indicating that these sediments likely recorded coherent paleomagnetic secular variations. The component inclination, declination as well as normalized remanence records of the three cores will be presented, compared and discussed in terms of Arctic Holocene geomagnetic field dynamics.
DE: 1521 Paleointensity
DE: 1522 Paleomagnetic secular variation
DE: 1530 Rapid time variations
DE: 1560 Time variations: secular and longer
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005