The geomagnetic field of the Ukrainian Carpathians and a 3D magnetic model of the Transcarpathian Depression

Abstract

The article presents the results of a qualitative and quantitative analysis of the geomagnetic field of the Ukrainian Carpathians and 3D magnetic modeling along the PANCAKE geotransect and Transcarpathian Depression, as well as a comparison of the obtained results with fault-block tectonics, deep structure, and distribution of a number of types of endogenous ore deposits and hydrocarbon accumulations. It is shown that the overthrust northeastern part of the Carpathian arc lies on the magnetic crust, and the southwestern one  — on its non-magnetic lower part, and between the Rava-Rus’ka and Krakovets and Pre-Carpathian faults, the Earth’s crust is magnetized throughout. For the territory of the Transcarpathian Depression, the regional and local components of the geomagnetic field were identified for the first time, geological and geophysical characteristics were provided, and their tectonic interpretation was proposed. A three-dimensional magnetic model of the Transcarpathian Depression was created taking into account the magnetization of rocks according to measurements. A detailed magnetic model of the upper part of the crustal section of the Transcarpathian Depression was developed. The connection of magnetic sources with fault zones was analyzed; the results were compared with the deep structure and distribution of ore deposits and hydrocarbon accumulations. The regional source with magnetism І=1.0 A/m is located within the Mukachevo Depression and is located at a depth of 6.0 km to 13 km. The local component of the geomagnetic field reflects the magnetic inhomogeneity of the Earth’s crust in the upper 3—4 km of the section and mainly reflects the volcano-tectonic structures and dike formations of the Vyhorlat-Gutyn Ridge, the Chop-Berehove Uplift, and the Velika Dobron’ Uplift. The maximum depths of magnetic sources (up to 3.5 km) and their magnetization (1.22 A/m) are characteristic of the structures of the Vyhorlat-Gutynsky Ridge, intermediate values of depths (2.0—3.0 km) and magnetization (up to 0.93 A/m) belong to the Chop-Berehove Uplift, and the minimum depths (up to 1.1 km) and magnetization (up to 0.7 A/m) are characteristic of the Velika Dobron’ Uplift. It is shown that the gas fields of Transcarpathia correspond to local positive magnetic anomalies and are localized above a deep magnetic source. Within the Berehove Uplift, positive anomalies and magnetic sources indicate andesiteporphyrite shafts and andesite domes of Sarmatian age associated with gold, gold-polymetallic and silver mineralization. A zone of antimony mineralization is associated with the Pannonian-Pontic volcanic structures along the southern foot of the Vyhorlat-Gutyn Ridge, and deposits and occurrences of bismuth and mercury correlate well with intrusive formations of the Dacian-Romanian age.