Three-dimensional magnetotelluric model along seismic profile 2T: An improved view on crustal structure in central Slovakia (Western Carpathians)

Abstract

We present the crustal-scale geophysical model based on the magnetotelluric method focused on 3-D model¬ling of the seismic 2T profile crossing the major Western Carpathian tectonic units in central Slovakia. The results of the 3-D modelling show substantial improvement in previous 2-D models of deep crustal structure in central Slovakia, mainly of the physically distinct tectonic segments and major geo-electrical regional structures like the zone of the Carpathian Conductivity Anomaly, which indicates the occurrence of the large-scale shear zone in the contact zone of the European platform and Inner Western Carpathians. High detail geo-electrical data in 3-D magnetotelluric (MT) cross section also allowed a better interpretation of other conductive anomalies. In the final integ-rated interpretation (combination of 3-D geo-electrical model, gravity data and seismic reflectors), it is shown that frontal part of the Inner Western Carpathians plate exhibits the transpressional tectonic style of the back-thrust Outer Western Carpathians (Flysch Belt) and Pieniny Klippen Belt units over the progressing Inner Western Carpathian thrust wedge. These back-thrusts form the southern branch of the accretionary structural fan – a large-scale transpressional flower structure typical mainly but not only for oblique con-vergent regimes. The southernmost segment of the profile with high whole-crust conductivity due to a higher heat flow caused by young volcanic activity indicates partial melting in the middle and lower crust.