HR: 1340h
AN: GP43A-0930    [Abstracts]
TI: Reconstructing Holocene Paleomagnetic Secular Variation From High Arctic Sediments
AU: * Davies, M H
EM: mdavies@coas.oregonstate.edu
AF: Oregon State University, College of Oceanic and Atmospheric Sciences, 104 COAS Admin Bldg, Corvallis, OR 97330, United States
AU: Stoner, J S
EM: jstoner@coas.oregonstate.edu
AF: Oregon State University, College of Oceanic and Atmospheric Sciences, 104 COAS Admin Bldg, Corvallis, OR 97330, United States
AU: St-Onge, G
EM: guillaume_st-onge@uqar.qc.ca
AF: Université du Québec à Rimouski, Institut des Sciences de la Mer de Rimouski, 310 allée des Ursulines, Rimouski, QC G5L 3A1, Canada
AU: Cook, T L
EM: tcook@geo.umass.edu
AF: University of Massachusetts, Department of Geosciences, 611 North Pleasant Street, Amherst, MA 01003, United States
AU: Bradley, R S
EM: rbradley@geo.umass.edu
AF: University of Massachusetts, Department of Geosciences, 611 North Pleasant Street, Amherst, MA 01003, United States
AU: Werner, A
EM: awerner@mtholyoke.edu
AF: Mount Holyoke College, Department of Earth & Environment, 50 College Street, South Hadley, MA 01075, United States
AB: Paleomagnetic studies of Holocene sediments from high Arctic lake and marine environments are beginning to document reproducible patterns of paleomagnetic secular variation (PSV), both in direction and intensity. Here we present new paleomagnetic data from Lakes Murray (81°34` N, 69°54` W) and C3 (82°50` N, 78°00` W) in Ellesmere Island, Nunavut Canada, as well as Lake Linne (78°05` N, 13°45` E) in Svalbard, Norway. The natural remanent magnetization (NRM) of all three lakes was studied by progressive alternating field (AF) demagnetization of u-channel samples. Though variable from lake to lake, the sediments preserve a generally strong, stable, well-defined (MAD <5) magnetization. Component inclinations are consistent with historical predictions and those expected for a geocentric axial dipole (GAD). Multiple records have been obtained from each lake, and varve and radiocarbon-based independent chronologies are being developed. Although these sediments represent a range of depositional environments, accumulation rates, and magnetic mineral assemblages, the records are largely consistent. Initial results from the laminated section of Murray Lake's sediments suggest that the record extends back at least 4500 years, providing one of the longest independently dated Holocene PSV records from the Canadian high Arctic. Comparisons will be made with previously obtained and independently dated records from the Beaufort Sea and Sawtooth Lake (Ellesmere Island), other non-independently dated PSV records from Arctic lakes, as well as both historic and prehistoric geomagnetic field models.
DE: 1500 GEOMAGNETISM AND PALEOMAGNETISM
DE: 1521 Paleointensity
DE: 1522 Paleomagnetic secular variation
DE: 1535 Reversals: process, timescale, magnetostratigraphy
DE: 1560 Time variations: secular and longer
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting