Geophysical processes and biosphere: article

Аnnotation: This paper presents results of the comprehensive study of electrical properties of the upper part of the Earth’s crust according to the lateral electric logging data of the Kola superdeep well SG-3 and according to the deep and super-depth soundings with controlled sources, as well as with electrical profiling data on the day surface. The paper considers the possibility of extrapolation of the Kola SG-3 temperature field to a depth below the well, up to the Moho boundary, taking into account the MHD sounding data with the «Khibiny» source and with the use of industrial power lines («FENICS» experiment). The geological and geophysical data were interpreted in the Kola SG-3 section and on the surface to search for homologs and interpret the nature of the intermediate conducting layer of dilatant-diffusive nature (the DD layer) found in the upper part of the Earth’s crust of the Baltic Shield at depths from 2-3 to 7-8 km. Based on the latest data of remote deep sounding (experiment «Murman-2018»), it was concluded that in the vicinity of the Kola SG-3 at a depth of 10-12 km, a boundary of «impermeability» for direct current (for the galvanic mode) is displayed. The geodynamic interpretation of the obtained data was carried out taking into account the model of V.N. Nikolaevsky [1996]. It has been suggested that the new boundary most closely corresponds to the transition area between brittle and quasi-plastic states of the Earth’s crust, which is consistent with the results of the Kola SG-3 logging and with the general results of ultra-deep drilling.