Deep Electrical Resistivity Structure of the European Lithosphere in Poland Derived from 3-D Inversion of Magnetotelluric Data

This paper presents a three-dimensional (3-D) model of the resistivity distribution in the European lithosphere at the junction between the East European Craton, the Palaeozoic Platform of Western Europe and the Carpathians. The model was created by inverting the magnetotelluric and geomagnetic deep sounding data from 593 points collected over the last 50 years. ModEM code was used to invert the data and obtain the conductivity distribution model. The full size of the mesh with edges was 3000 by 3000 kms and 600 kms in the vertical direction, and the modelling field was digitized with 104 x 104 x 52 (+ 10 air) cells in geographic orientations. A trial-and-error approach was applied to select the best model parameters, such as the starting model and the covariance matrix. The results show a variable thickness of the sedimentary layer, increasing westward, and the presence of deep and extensive conductive anomalies in the crystalline crust. Early Permian continental rifting responsible for the SW-ward lithospheric thinning, localised crustal stretching and subsidence of a broad sedimentary basin had a primary impact on the distribution of resistivity anomalies. While the pre-rift tectonic features have little impact on the resistivity structure, the effects of Late Cretaceous-Paleogene accretion of the Western Carpathians and inversion of the Permian-Mesozoic Polish Basin are clearly detectable in the resistivity pattern. Consequently, our study highlights the role of relatively young tectonic processes in the evolution of a transition zone linking old and stable Eastern Europe with younger and mobile Western Europe.

Automated summary

This paper presents a 3-D model of resistivity distribution in the European lithosphere at the junction between different geological regions. The model is obtained by inverting magnetotelluric and geomagnetic deep sounding data. The results show variations in sedimentary layer thickness and the presence of deep and extensive conductive anomalies in the crust. The study highlights the role of early and relatively young tectonic processes in the evolution of the region.