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32nd Annual Arctic Workshop Abstracts
March 14-16, 2002
INSTAAR, University of Colorado at Boulder

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HOLOCENE RECORDS OF PALEOSECULAR VARIATION FROM THE ARCTIC: ELLESMERE ISLAND AND THE NORTH ICELAND SHELF

AUTHORS

STONER, JOSEPH S. INSTAAR, University of Colorado.
Patridge, Whitney . University of Massachusetts.
Francus, Pierre . University of Massachusetts.
Andrews, John T. INSTAAR, University of Co.
Bradley, Raymond S. University of Massachusetts.
Andrews, John . University of Pittsburgh.
Koc, Nalan . Norsk Polarinstitutt.
Retelle, Mike . Bates College.

Because of its proximity to the magnetic pole, the Arctic is an important location for understanding past geomagnetic behavior. Unfortunately, few observations from high latitude locations exist and, therefore, our knowledge of Holocene geomagnetic field behavior is incomplete. Towards resolving this issue, we present initial results of a u-channel paleomagnetic study of 2 cores from 2 lakes in Ellesmere Island, Nunavut in the Canadian high Arctic and one long piston core taken off the north coast of Iceland. Sawtooth Lake, is an oligotrophic lake located at the southwestern part of Forsheim peninsula. Core SS99-10-6B (Lat: 7920'58.89"N, Long: 8356.12.65W, water depth of 80.62 m; length 463 cm) is one of several vibracores and glew cores taken during the 1999 field season. Murray Lake, also oligotrophic, is located on the eastern coast of Ellesmere Island, near the Archer fjord. Core ML01-03-VC1 (Lat: 8134.328 N. Long. 6954.291 W, water depth 45.5 m; length 515 cm) was taken during the spring of 2001 and constitutes one of two vibracores and several short glew cores taken from the north basin. Sawtooth Lake contains annual clastic laminations, providing a varve chronology that is estimated to extend for the last 2600 yrs with a sedimentation rate of approximately 180 cm /kyr. Murray Lake is intermittently laminated and its chronology is unsure. MD99-2269 (Lat: 6613.93 N. Long. 2315.93 W, water depth 106 m; length 2530 cm) was collected during the summer of 1999 as part of the international IMAGES-V (International Marine Past Global Change study) campaign aboard the Marion Dufresne II. Chronology for this core is provided by 10 AMS 14C dates and several ash layers with known ages, suggesting that this record covers approximately last 12,000 yrs with an average sedimentation rate of approximately 200 cm/kyr.

The natural remanent magnetization (NRM) was studied by progressive alternating field (AF) demagnetization of u-channel samples, which indicate a strong, stable single component magnetization for all three cores. The inclination varies about a mean close to the expected inclination for each cores site latitude. Comparisons of the inclination, declination, and relative paleointensity records between Sawtooth and Murray Lakes allow an optimized correlation to be made that takes into account the full magnetic vector. If this can be substantiated, this suggest that an accurate representation of the full magnetic vector can be obtain from High Arctic Lakes and intern be used as a chronostratigraphic tool. Additionally these data appear to be consistent with discrete sample paleomagnetic data from Cape Hurd Lake, Devon Island and therefore suggest that these sediments may be recording a regionally consistent geomagnetic pattern. Patterns of secular variation (inclination and declination) from MD99-2269 are similar to those derived from previously published data from Icelandic lakes and are generally consistent with the patterns observed from Ellesmere and Devon Islands. Features similar to those found in published records from North America and Europe are also observed.

 

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