T11 Environmental Magnetism, Magnetic Stratigraphy, and Magnetic Field Modeling

Sunday, 18 October 2009
8:00 AM - 12:00 PM
Portland Ballrooms 251/258

HIGH-RESOLUTION HOLOCENE PALEOMAGNETIC SECULAR VARIATION RECORDS FROM ICELAND: MARINE – TERRESTRIAL SYNCHRONIZATION

Paper number: T11-4
Program: Technical Sessions
Time: 8:50 AM – 9:10 AM

Authors

Abstract

Iceland is located within a sensitive part of the North Atlantic, both in regard to atmospheric and oceanographic fronts and with regard to the geomagnetic field. To compare terrestrial and marine paleoclimate proxy records from this area in a meaningful way requires an independent correlation tool. Regional scale changes in the geomagnetic field as preserved within magnetic minerals in the sediments can provide a sediment paleomagnetic secular variation (PSV) record that offers the unique potential to synchronize the marine and terrestrial sediment cores. We present high-resolution Holocene paleomagnetic records from two Icelandic lacustrine environments. Lake Haukadalsvatn from west Iceland, and Lake Hvítárvatn central Iceland. The sedimentation rates are extremely high in these lake cores, ~1.6 m / kyr for Haukadalsvatn and up to 5 m/ kyr for Hvítárvatn. The paleomagnetic signal was studied using alternating field (AF) demagnetization of u-channel samples. These measurements document an extremely strong and stable single component, low coercivity magnetization consistent with magnetite as the primary remanence carrier. Variations in declination and inclination are compared with a well-dated paleomagnetic secular variation record from MD99-2269 (Stoner et al., 2007) for the last ~10 ka, allowing us to correlate variations that are consistent and reproducible. The similarity between these records suggests that the paleomagnetic synchronization approach provides a valid means of dating Icelandic sediments. Comparisons between the ages predicted form this and those derived using other techniques will be presented. In addition, the detailed paleomagnetic data set provides significant value to the geomagnetic community that seeks to understand the dynamics of geodynamo and requires data of historical type resolution further in the past.

Stoner, J.S., Jennings, A.E., Kristjánsdóttir, G.B., Dunhill, G., Andrews, J.T., Harðardóttir, J. 2007 A paleomagnetic approach toward refining Holocene radiocarbon-based chronologies: Paleoceanographic records from the north Iceland (MD99-2269) and east Greenland (MD99-2322) margins. Paleoceanography, 22, 1-23.