Findings from the deep magnetotelluric studies in the area of the Sloboda Geodynamic Intersection (East European platform)

Abstract

The Sloboda Geodynamic Intersection is considered as an area of convergence for major segments, aulacogens, faults, and suture zones of the East European Platform.Between 2020 and 2022, researchers from the Geological Faculty of Lomonosov Moscow State University and the Geoelectromagnetic Research Center (GEMRC IPE RAS) conducted deep magnetotelluric surveys in this region. The surveys were performed along the Pushkiny Gory – Andreapol, Sebezh – Velikiye Luki – Rzhev, and Ostrov – Ostashkov profiles. Through qualitative analysis of the collected data, the dimensionality of the studied medium, the total longitudinal conductance of the sedimentary cover, and the dominant strike direction of conductive structures were assessed. Quantitative interpretation using 1D, 2D, and 3D inversions resulted in geoelectric models comprising a conductive sedimentary cover and a highly resistive basement. Within the depth range of 10–40 km, transcrustal zones of enhanced electrical conductivity were consistently identified, interpreted as the southwest extension of the Ilmen-Ladoga anomaly. These conductivity anomalies are attributed to the deep submergence of heavily tectonized and metamorphosed sedimentary rocks, initially saturated with organic and carbonate matter.

Keywords

• magnetotelluric soundings
• crustal conductive anomalies
• inversion