The conductivity structure across the Trans-European Suture Zone from magnetotelluric and magnetovariational data modeling

Abstract

To achieve an electrical conductivity model of the Trans-European Suture Zone (TESZ), magnetotelluric measurements in the period range of 10–20,000 s along two almost parallel profiles with a total of 65 sites, starting from the North German–Polish Basin, crossing the TESZ and ending on the East European Craton, were conducted. Magnetovariational responses were combined with other magnetotelluric transfer functions, because for large periods they are free of near-surface galvanic distortions and thus lead to more reliable resolution of deep structures. Following the results of strike and dimensionality analysis, input data for two-dimensional inversion were created by rotating all transfer functions to the common strike direction. Models derived from different combinations of data were compared and several sensitivity analyses were carried out. The results show a highly conductive layer of sediments (saline aquifer) and the TESZ as a broad region of enhanced conductivity. It was also clarified that the lower crust and upper mantle of the East European Craton (EEC) are more resistive than the Paleozoic Platform (PP, underlying the Northeast German Basin) and this resistivity extends to the greater depths.