Collaborative Research: Geomagnetic Field for the Last 5 Ma

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9804737Opdyke This proposal is for a collaborative multi-institutional project to improve the quality and spatial and temporal distribution of the 0-5~Ma paleomagnetic record from lava flows. The ultimate goal of the project is to improve our understanding of how the geodynamo controls the observed magnetic field. Specifically: 1) Do the mid-high latitude flux lobes and north polar low seen in the historical and 0-3 kyr (only northern hemisphere lobes resolved) records persist over paleomagnetic time scales, and 2) Are there are hemispheric differences in the time-averaged field and paleosecular variation? In order to address these issues, the P.I.s have planned systematic paleomagnetic sampling of flows covering as wide an age range as possible at each location, followed by detailed high quality laboratory analyses. Wherever possible paleointensity as well as directional records will be acquired. Fourteen globally distributed sites have been selected for sampling: the plan is designed to complement existing data of high quality, and avoid duplication of known resampling being carried out by other international groups. The specific places chosen include two very high latitude locations, a north-south transect through the Americas, and a site from south-eastern Australia.