Electrical Conductivity of the Basement of East European Platform in the Southeastern Ladoga Region from Magnetotelluric Data

—The paper presents the results of magnetotelluric soundings conducted in 2018–2019 in the southeastern Ladoga region for studying the deep geoelectric structure of the basement of the East European platform at the junction of the Russian plate with the Fennoscandinavian shield. The results of noise suppression processing of the observations on the 180-km Tikhvin–Vinnitsa profile and the invariant analysis of the obtained magnetotelluric and magnetovariational transfer operators are discussed. A geoelectrical model of the Earth’s crust along the profile down to a depth of 50 km is constructed by two-dimensional inversion. The model clearly reflects the structures of the southeastern segment of the Ladoga crustal conductivity anomaly confined to the extended Ladoga-Bothnian tectonic zone at the boundary of the Archaean (AR) and Proterozoic (PR) domains of the shield. Fundamental features of the similarity between the new 2D model of the Ladoga anomaly and the similar model previously constructed for the Vyborg–Suojärvi profile on the northern coast of Lake Ladoga are revealed: the general southwestward dip of the crustal conductive structures and a significant increase in their integral conductivity at the depths of 15–20 km within the southern segments of the profiles. A preliminary geological interpretation of the constructed resistivity section along the Tikhvin–Vinnitsa line is presented.