Geoelectrical model of the Earth’s crust along the Shu-Sarysu geotraverse according to magnetotelluric soundings

Aigerim Tleubergenova, Gulzada UMIROVA, Oleksii KARPENKO, Aliya Maussymbayeva

2023

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DOI 10.33271/nvngu/2023-3/005
Data confidence 70 medium
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Abstract

Purpose. To study and assess the possibility of effective application of electrical prospecting by magnetotelluric sounding (MT-sounding) and to determine the range of geological problems to be solved in the geoelectric conditions of the Shu-Sarysu geotraverse. Methodology. The issues of methodology of modern technologies of field observations, peculiarities of processing and interpretation of MT-sounding data are considered, which showed that modern instrumental and methodical electrical survey technologies of MT-sounding allow obtaining results of field measurements of increased reliability, due to their accuracy, productivity, mobility, noise immunity, level of automation. To identify the main features of the geoelectric structure of the Earth’s crust and the upper mantle, the modern technique of interpreting MT data allows for 1, 2D inversion of the effective curves of apparent resistivity and impedance phase. Findings. Based on MT-sounding data, a geoelectric section of the Shu-Sarysu geotraverse was constructed, characterizing the position and morphology of five geoelectric boundaries in the crustal section in the 0–40 km depth interval. The identified five geoelectric horizons show good coincidence with the conventional seismic horizons and confidently correlate with the geological references established by GIS data. Originality. On the basis of MT-sounding studies, the geological interpretation of the structure of suprasalt and subsalt structural-formation complexes is presented; the geological efficiency of MT-sounding electrical prospecting in revealing the complex structures in the conditions of the Shu-Sarysu geotraverse is shown. On the basis of model constructions of the geoelectric section, new data on the deep geological structure of the Shu-Sarysu geotraverse were obtained: new data on the structure of Mesozoic terrigenous-sedimentary rock complexes and the Paleozoic part of the section with the allocation of the supposed faults; on the basis of MT-sounding results, recommendations for further detailed geological exploration work were given. Practical value. A comprehensive interpretation is recommended of the obtained MT-sounding data together with the results of geological and geophysical research on the regional profile in order to establish search criteria for the discovery of mineral deposits and the prospects of gas content in the area.