Direction and paleointensity of the Earth`s magnetic field during reversals and excursions recorded in basaltic lava flows (0.5 - 15 Myr)

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During field trips to the Hawaiian and Canary Islands five sequences of lava flows have been sampled. Within these volcanic sequences several reversals and excursions are recorded. Based on first paleomagnetic and rock magnetic investigations the samples proved to be excellent recorders of the past Earth's magnetic field. We intend to investigate the variations of the direction and absolute paleointensity during these transitional states and extend this research to volcanic sequences in the southern hemisphere (Fernando de Noronha). This ist an especially important subject for paleomagnetic research, since there are only fex recordings of the transitional field in lavas from the southern hemisphere. The presently available records are too few to decide whether a transition is dominated by a dipolar or a nondipolar field configuration. The sampling of additional volcanic sequences will provide an opportunity to determine the paleosecular variation in different hemispheres. Detailed rock magnetic investigation and ore microscopy will ascertain that high quality paleointensity data are obtained. By comparison of our results with published data we will test the hypotheses of an interaction between mantle heterogeneities and the geodynamo as well as investigate possible transitional field configurations of reversals and excursions.