Reconstruction of geomagnetic paleointensity over the past 350,000 years based on Beryllium-10 records from two high accumulation sites in the Atlantic Ocean

点击翻译按钮获取中文摘要

A record of geomagnetic paleointensity over the past 350,000 years will be generated based on high resolution 10Be-Records from two highly accumulating marine sediment cores: ODP Leg 172, Site 1063 and ODP Leg 177, Site 1089. To extract the global 10Be-production rate from the sedimentary records, a special transport-correction procedure is applied. This procedure comprises the Thorium-normalization method to correct for sediment redistribution and ocean model calculations to quantify the lateral transport of Th and 10Be in the ocean. The well known relation between relative geomagnetic dipole field strength and 10Be production rate is used to reconstruct geomagnetic paleointensity over the past 350,000 years. This provides a totally independent tool for the reconstruction of the Earth`s magnetic field strength that can be used complementary to conventional paleomagnetic methods. By using an inverse approach, variability of North Atlantic deep water formation on glacial/interglacial timescales and/or a possible solar long term magnetic variability can be assessed by analyzing the deviations between the 10Be-based and magnetization-based reconstructions of geomagnetic paleointensity. Furthermore, the variability of the "lock in depth" of the magnetization signal may be examined by analyzing the offset in time between the 10Be signal and the magnetization signal.