Parameters of the Magnetoactive Layer of the Lithosphere for the Siberian Platform—Transbaikalia Profile Based on WDMAM 2.0 Model Data

Abstract

The results of the determination of the depths to the centroid, the top and bottom boundaries of the magnetoactive layer along the meridional profile starting on the Siberian Platform (60° N, 113° E) and ending in Transbaikalia (50° N, 113° E) are presented. The calculations are performed based on analysis of azimuthally averaged Fourier power spectra of the lithospheric geomagnetic field assigned by the global WDMAM 2.0 model. The obtained estimates show that the depth to the top boundary of the magnetoactive layer along the selected profile is ~2.0 km, but the depths to the centroid and the bottom boundary decrease in the southern direction from 16.6 and 37.4 km to 13.6 and 25.0 km, respectively. Comparison of the parameters of the magnetoactive layer to the structure of the lithosphere in the study region and the distribution of depths of earthquake hypocenters makes it possible to determine that the magnetoactive layer approximately coincides with the seismoactive layer for the North Muya region of the Baikal rift. The magnetoactive layer along the entire profile is located within the Earth’s crust; its thickness is directly proportional to the lithospheric thickness and is inversely proportional to the temperature of the upper mantle. The results are consistent with hypotheses of passive formation of the Baikal rift and are interesting for further geological-geophysical studies in this region, in particular, to determine heat flow and to construct substantiated models of lithospheric evolution.