Geoelectric model of the sedimentary cover in the junction zone of the Vilyui Syneclise and the Pre-Verkhoyansk marginal trough

Abstract

This article presents the results of magnetotelluric studies conducted in the junction zone of the Vilyui Syneclise (Linden Depression) and the Pre-Verkhoyansk Marginal Trough. The study aimed to construct a geoelectric model of the sedimentary cover of this area based on a series of latitudinal and meridional profiles. According to the results obtained, the geoelectric section of the study area comprises seven geoelectric horizons, six of which are formed by sedimentary deposits of the platform cover and the seventh by Precambrian basement rocks. Notably, the seventh horizon is identified only in the western part of the study area and is characterized by the highest resistivity values. Its roof dips sharply from depths of 6.5–7 km to 15 km and presumably corresponds to the roof of the Proterozoic basement. In addition, a laterally extended conductive region (ρ = 10–13 Ω⋅m) is traced within the 5–10 km depth interval, with its roof rising to depths of 1.5–2.0 km in the eastern part of the study area. This region is complicated by a series of subvertical conductive zones with lower resistivity values (ρ = 2–6 Ω⋅m). Finally, their map position indicates that they are oriented parallel to the faults bounding the thrust structures and may represent thrust-related structural traps.