Tectonic Layering of the Platform Cover and Preplate Complex of the Scythia‒Turan Plate in the Caspian Sea

Tectonic dislocations of the preplate Permian‒Triassic complex and in the overlying platform cover of the northern Caspian Sea have been studied. The tectonic stratification of the preplate complex has been established due to the development of gently dipping thrusts and disruptions in its section. Their formation is associated with collisional processes that accompanied the closure of residual basins of the Paleotethys Ocean. In its subsequent development, the young platform periodically experienced horizontal compression, which led to resumption of movement along buried thrusts. As a result, asymmetric anticlines were formed in sediments of the cover in the frontal parts of the thrusts. In addition to this type of structure, numerous layered tectonic faults and rootless anticlines have been identified in the sediments of the plate complex. The largest of the faults, experiencing transformation of horizontal to vertical displacements in the head parts of the plates, penetrated the overlying sediments, tearing the sedimentary cover to its full capacity. The reason for their formation is the transpressive effect of tangential stresses transmitted to the platform from the area of the Alpine orogeny of the Caucasus. The important role of tectonic deformations in the formation of oil and gas accumulations in the preplate complex and platform sediments is shown.