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LATE HOLOCENE PALEOMAGNETIC SECULAR VARIATION (PSV) FROM NUNAVUT, CANADA: DEVELOPMENT OF A DATING CURVE

STONER, JOSEPH S  University of Colorado.
Francus, Pierre  Institut national de la recherche scientifique.
Bradley, Raymond S  University of Massachusetts.
Retelle, Michael J  Bates College.
Abbott, Mark B  University of Pittsburgh.
Patridge, Whitney  University of Massachusetts.
Channell, James E T  University of Florida.

Historical observations and Pleistocene paleomagnetic data indicate the rather unique properties of the geomagnetic field in the polar regions. To examine the Holocene paleomagnetic record from the Arctic, we have undertaken a u-channel paleomagnetic study of late Holocene sediments from multiple cores taken from two lakes on Ellesmere Island (Nunavut, Canada). Sawtooth Lake (79 21 N, 83 56 W) is an oligotrophic lake located in the southwestern part of the Forsheim peninsula. Murray Lake (81 34 N, 69 54 W) is also oligotrophic and is located on the eastern coast of Ellesmere Island, near the Archer Fjord. Both lakes contain annual clastic laminations, providing varve chronologies that document a sedimentation rate of ~200 cm /kyr for the last ca 2600 yrs at Sawtooth Lake, and ~50 cm/kyr for the last ca 4000 yrs at Murray Lake. U-channel paleomagnetic data using progressive alternating field (AF) demagnetization show that the sediments of both lakes preserve a strong, stable, single component magnetization that can be tied to the historical record. A late Holocene PSV record for Ellesmere Island can now be established for the last 2600 yrs based the agreement between multiple cores from each lake and similarities of inclination, declination and relative paleointensity between lakes. This record documents high amplitude geomagnetic field changes that are significantly larger than anything in the historical record including the ~1000 km migration of the North Magnetic Pole during the last century. These records are compared with initial results from Devon Island (Cape Hurd Lake & Cape Eardley Wilmont Lake), Cornwallis Island (Depot Point Lake) and Bathurst Island (Danielle Point Lake) that support the idea that under the correct conditions PSV can be used as a tool for dating Arctic sediments.


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