A record of the behavior of the geomagnetic field in the sediments of Lake Baikal (BDP-99 borehole)

摘要

The relative paleointensity of sedimentation is studied for sediments stripped by deep-water drilling in Lake Baikal (BDP-99 borehole). Two intervals are considered: 0-420 ka (Brunhes chron) and 1.05-1.09 Ma (before, during, and after the Matuyama-Jaramillo reversal). For these intervals, curves of the ideal magnetization of samples are plotted.The paleointensity data obtained along the borehole section reveal four excursions for the Baikal sediments whose identification on the inclination-depth curve is complicated.The lower part of the section (Matuyama-Jaramillo subzones) shows a paleointensity decrease by a factor of five or more relative to periods of invariable polarity.