Structural features of the Kungur salt-bearing formation and salt tectonics in the South-East of North Caspian Basin

Abstract

The article analyzes the features of the formation of the Precaspian salt basin and salt dome tectonics in the southeast of the depression. It presents a model of a salt accumulation basin that is linked to its isolation from the Paleotethys Ocean and a unidirectional water inflow. These factors resulted in the deposition of evaporites including thick layers of rock salt under conditions of intense aridification. The halotectonic mechanisms responsible for the formation of salt domes and diapirs were found to be active, passive, and reactive. The first and last cases were identified through the involvement of fault tectonics in the development; the mechanism of passive halotectonics is associated with a prograding wedge, or gradual lateral buildup, of the strata and the rise in the load of overlying rocks. Salt domes are considered to be related to the filling of the basin with terrigenous clastics and the movement of salt layers from the sides to the center. Later, salt diapirs were manifested due to tectonic stress during the formation of the northern margin of the Paleo- and Neotethys, its closure and the collision of small Iranian continental blocks, island arcs and accretionary prisms originating from the south of the Caspian basin.