Abstract

The major paleogeographical events of the Pont-Caspian region during the last 30 k.y. occurred non-synchronously: the Neoeuxinian basin correlates with the Caspian Khvalynian transgression. During the peak of the Khvalynian transgression Caspian waters flowed via the Manych Strait into the Neoeuxinian basin. Faunal composition points to a one-way migration of molluscs from the Caspian to the Black Sea. The species composition of the Eastern Manych reflects an approximate salinity level of 10–12‰. Faunal findings of the Eastern Manych indicate different stages of water drainage of the Early Khvalynian transgression into the Neoeuxinian basin. The earliest registered stage is found in cite Zunda-Tolga and the latest – in the Chogray dam cite. The least saline species are found here. The geological structure of the sections shows a sequential change of hydrological regime in the strait from stagnant to shallow water non-stagnant and to highly dynamic running. The composition of taphocenosises of Eastern Manych Khvalynian fauna is proximal to mollusk assemblages of the maximum of Early Khvalynian transgression in the North-Western Caspian region. It was the last paleontologically proved epoch of the existence of the strait.

Keywords: biostratigraphy, molluscan assemblages, Khvalynian transgression, Neoeuxinian basin, Manych