Deconvolution of paleomagnetic directions from marine sediments in the Boso Peninsula, Japan, and its implications for the matuyama-brunhes transition field

Abstract

The method of deconvolution of post-depositional DRM (detrital rémanent magnetization) is applied to the paleomagnetic directions of continuous sedimentary sections from two sites in the Boso Peninsula, Japan. These sections have different accumulation rates and cover a time span of about 1000 years that includes the Matuyama-Brunhes reversal. Since the remanences are thought to be of the postdepositional DRM origin, a new deconvolution method with an exponential fixing function is applied. The deconvolution restores relative intensities of three components in the original fields from the remanence directions. As a result, the half-fixing depth is estimated to be 21 cm and the three-dimensional plot of the relative intensity is given. In the diagram of X and Z components, the polarity change in the geocentric axial dipole field with some additional field is recognized during the main reversal, while there seems to be no correlation between X and Y. After the deconvolution, the VGP path during the main reversal does not show longitudinal confinement, but does show longitudinal drift near the equator.