Structure of the Triassic Deposits of the Peschanomys–Rakushka Oil and Gas Accumulation Zone

Folding-thrust dislocations formed under the influence of lateral compression forces are quite widely represented in the sedimentary cover of the Scythian-Turanian plate. Horizontal tectonic movements are usually accompanied by lateral displacement of individual blocks of the Earth’s crust separated by strike-slip faults. In contrast to thrust dislocations, information about the presence of strike-slip faults for the Scythian-Turanian plate is extremely limited. This problem is considered on the example of dislocations of Triassic sediments of the Peschanomyssk–Rakushechnaya uplift zone of the South Mangyshlak trough. A detailed lithological and stratigraphic analysis of sections of Triassic sediments exposed by deep wells within this zone was carried out. Characteristic lithological strata were identified and their stratigraphic binding was performed. The shifting nature of regional basement faults was established. Many of them were active in the following periods, characteristic shear deformations were formed in the sedimentary cover as a result of this activity. Morphological features of dislocations that are traps of oil and gas were established. The authors’ reconstructions are based on their comprehensive analysis of geological and geophysical materials, including data from high-precision large-scale aeromagnetic surveys, reflected wave seismic exploration, deep drilling, and remote surveys. In order to restore the history of the development of the territory as a whole and the folded-discontinuous dislocations complicating it, paleotectonic constructions were carried out. The information provided in this paper on this problem allows us to take a fresh look at the geodynamic situation of the formation of platform territories, and may also contribute to solving some oil and geological problems, since oil and gas accumulations are often concentrated in areas of wrench faults.