The correction of TRM deviation induced by AMS and its application

Abstract

Based on the assumption that the order of magnitude of the anisotropy eigenvalue ratios of thermal remanent magnetization (TRM) is expected to be the square of the principal susceptibility ratios in anisotropic multidomain magnetic assemblages, a concrete correction formula is derived which can be used to correct the TRM deviation induced by the anisotropy of magnetic susceptibility (AMS) away from the ambient field, and successfully applied to the practical paleomagnetic research in Yueshan diorite (China) and Flamanville granite (France). An interesting discovery is that TRM direction is deflected away from that of the paleofield in each site. In contrast, the overall mean TRM direction is quite a good estimation of the paleofield direction, because the major axis of susceptibility ellipsoid are in the radial distribution. -Authors