THE DEPTH TO MAGNETIC SOURCES IN THE ARCTIC AND ITS RELATIONSHIP WITH SOME PARAMETERS OF THE LITHOSPHERE
A.I. Seredkina, S.V. Filippov
Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propagation, Troitsk, Russia
Keywords: Magnetic sources, geomagnetic anomalies, EMAG2v3 model, WDMAM 2.0 model, Fourier spectrum, lithosphere, Arctic
Abstract
The depth to magnetic sources in twenty Arctic tectonic provinces is determined from azimuthally averaged Fourier power spectra of geomagnetic anomalies according to the EMAG2v3 and WDMAM 2.0 global models. The resulting depths to the centroid and bottom of the magnetic lithosphere are more reliable than the depth to the upper magnetic boundary. The depth to the bottom of magnetic sources, corresponding to the Curie point depth, varies from 25.3 to 38.1 km in different provinces. The Curie point depth estimates are correlated with several parameters of the lithosphere. They are directly proportional to the lithospheric thickness and inversely proportional to average upper mantle temperatures, but the relationship with the intensity of long-wavelength satellite magnetic anomalies and crustal thickness is poor. The magnetic sources are located at crustal depths in most of the provinces, but the upper mantle may be magnetic beneath deep-water oceanic basins and the Laptev Sea. The results for the Laptev Sea shelf support a passive mechanism of current lithospheric extension in the area.
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