Akchagylian Hydrospheric Phenomenon and Its Connection with Deep Geodynamics

Hydrosphericdisturbances are one of the defining elements of the development of both the stratigraphic scale and the scale of planetaryperiodization during the Late Cenozoic. The most exotic in paleogeographic and sedimentation-biotic terms is the Akchagylianbasin—anomalously elongated deep to the north and characterized by a typology of transition from a brackish water regime to asemi-marine and marine one. The sea transgression in the Akchagylian time reached 200 or more meters, which could not butsignificantly impact the accumulation of precipitation and the climatic conditions of this period. Based on the detailedstratigraphic, structural-tectonic, palebiogeographic, and paleomagnetic analyses, the boundaries and volume of theAkchagylian stage in the Eastern Paratethys region were revised. For the first time, the land-sea boundaries for this regionduring the period of the maximum Middle Pliocene (Akchagylian) transgression are distinguished. A clear connection is shownbetween the development of the Akchagylian basin with different tectonic elements. This research can be used to develop anenhanced strategy for prospecting hydrocarbon deposits in the region under study.