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GEOLOGICAL STRUCTURE OF THE PRE-JURASSIC BASEMENT OF THE CENTRAL PART OF THE KRASNOLENINSKY SWELL IN THE LIGHT OF NEW GEOLOGICAL AND GEOPHYSICAL DATA

D. A. Sidorov 1, L. V. Lapina 1, N. V. Kholmanskikh 1, D. V. Emelyanov 2, L. P. Melnikov 2, D. A. Fedorov 2

1 Tyumen Petroleum Research Centre LLC, Tyumen, Russia; 2 RN-Nyaganneftegaz JSC, Nyagan, Russia

The article reviews features of the pre-Jurassic geological structure of the Krasnoleninsky Swell, located on the western edge of the West Siberian petroleum basin. New geological and geophysical materials are presented enabling significant clarifification of the relationships pattern between Precambrian, Paleozoic and Triassic formation complexes. The stratification of the pre-Jurassic section is based on previously known age determinations and datings made in recent years by high-precision methods. The analysis of mode of occurrence of Pre-Jurassic rock complexes is based on the interpretation of seismic materials and gravity and magnetic data. The proposed model of the Krasnoleninsky Swell pre-Jurassic basement is characterized by the significantly reduced volume of pre-Cambrian formations due to the expansion of the Paleozoic complexes area, local Paleozoic depressions at the base of the Yem-Yegovskaya and Kamennaya peaks and linear zones of development of Triassic terrigenous-volcanogenic rocks on the Talinskaya Terrace and in the Palyanovsky trough have been identified. The conclusion is made about the long and complex history of the basement structure formation in the zone of collision junction of divergent Ural and Central-West Siberian folded systems.

Keywords: Krasnolensky Swell, base, pre-Jurassic basement, Paleozoic, Triassic, geological structure, stratification, formation complexes.

DOI 10.20403/2078-0575-2021-4-58-69

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