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Electromagnetic methods for forecasting of mineral resources occurences


Work number - M 13 FILED

Presented Institute of Geophysics, National Academy of Sciences of Ukraine

Authors:
Anton KUSHNIR – Doctor of Geological Sciences

The scientific work is devoted to the study of the earth's crust and upper mantle geoelectric heterogeneities of the various geological structures of Ukraine on the basis of the construction of the three-dimensional models of the electrical resistivity distribution according to the experimental MT/MV data. It deals with the explaining of the high-electrical conductivity anomaly nature based on the results of the geological and geoelectrical data complex analysis and their study as one of the factors of the geodynamic processes for the ore mineralization and hydrocarbon search.

The three-dimensional models of the electrical resistivity distribution of the earth's crust and upper mantle, both local and regional, were constructed and analyzed. The local models are basic-metabasic structures (Tarasivka and Troyanka massives) of the Yatran block of the Golovanivsk suture zone. The regional ones are the central part of the Ukrainian shield (Ingul megablock, Golovanivsk and Ingulets-Kryvyi Rih suture zones), the Northern Dobrudja and the Pre-Dobrudja depression, the Crimean-Black Sea region.

According to the research, the geoelectric heterogeneities in the earth's crust and upper mantle of Ukraine were revealed, they are characterized by the anomalously low and anomalously high electrical resistivity values. The conductivity zones that reach the surface are characterized by the subvertical heterogeneity and assemble the galvanically linked system. It spatially coincides with the deep faults of the different rank that are distinguished according to the geological data. The earth's crust independently of the geological and tectonic region is characterized by anomalous conductivity layers, the upper edge of which is observed at the different depths from 2 to 20 km with an apparent resistivity up to 100 Ohm∙m. The geoelectrical heterogeneity of the upper mantle was revealed in the Carpathians, Pre-Dobrudja and Crimean-Black Sea regions, and only fragmentarily under the Ukrainian shield, the Pripyat depression, and the Dnipro-Donets basin.

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