Character of Holocene paleomagnetic secular variation in the tangent cylinder: Evidence from the Chukchi Sea

Abstract

We have carried out a paleomagnetic study on three deep-sea cores from the Chukchi Sea (72°N) in order to characterize the Holocene paleomagnetic secular variation (PSV) in this high-latitude region. The Chukchi Sea lies within the geomagnetic-field tangent cylinder and PSV variability in this region might be expected to have a different pattern than PSV at sites located outside the tangent cylinder at lower latitudes. We have recovered correlatable directional PSV records and relative paleointensity records from all three cores. 15 radiocarbon dates were used to develop a chronostratigraphy for the PSV records. These records constitute the highest-resolution full-vector PSV records ever recovered from such high latitudes. We have compared our results with other previous studies from the region and find that our overall PSV is consistent with these other studies, although there are sometimes age differences up to 1000years between correlatable PSV features. Our statistical PSV characteristics indicate that field variability (VGP angular dispersion) is lower than in regions just south of the Chukchi Sea and outside the tangent cylinder, but our records are probably not long enough to completely characterize PSV. However, our results are consistent with the only other published VGP angular dispersion results from inside the tangent cylinder (Antarctica, 79°S).