Depths to Lithospheric Magnetic Sources and Lithospheric Thermal Regime under the East Siberian Sea.

Abstract—We present the results of studying the depths to lithospheric magnetic sources under the East Siberian Sea. The azimuthally-averaged Fourier power spectra of geomagnetic anomalies have been calculated from the global model EMAG2v3, which is the most current compilation of marine, aeromagnetic, ground, and satellite geomagnetic surveys. The depths to the centroid, the upper and lower boundaries of the magnetoactive layer have been calculated from the obtained spectra by the centroid method. The analysis of the results included comparing the depth distributions with known data on the thicknesses of sediments and the Earth's crust, the depths of regional earthquake hypocenters, the surface heat flow, and the tectonic structure of the study region. It has been concluded that the depth to the upper boundary of the magnetoactive layer varies from about 0.4 km under the De Long High to 7 km under the New Siberian and East Siberian sedimentary basins. The depth to the lower boundary of the lithospheric magnetic sources varies from about 25 km under the De Long massif and the Podvodnikov Basin to 43 km under the New Siberian-Chukchi fold belt. In the considered territory, the lithospheric magnetoactive layer is located entirely within the Earth's crust under the continent, the New Siberian Islands, the De Long High, and the western section of the East Siberian Sea shelf. The upper mantle is magnetic under the eastern section of the shelf and the Podvodnikov Basin. The obtained results indicate stronger warming of the lithosphere in the north of the study territory: under the Podvodnikov Basin and the De Long massif, characterized by suboceanic and continental crustal types, respectively. [ABSTRACT FROM AUTHOR]