Genesis of the Baery knolls developed in the Northern Caspian Plain

There are many such forms on the North Caspian lowland, where the author and colleagues conducted detailed geologic and geomorphologic field surveys. On the south, the range of altitudes of Baer knolls (BK) reaches 10-12 m, and the hills have a general southwest orientation. The described landforms are the same BK as those developed along the Volga delta. The sediments composing the BK consist of alternations of clay, silt and sand. They contain a rich complex of brackish water ostracods, detritus and even whole shells, which indicate their subaqueous genesis. During the Late Khvalyn, currents dominated in a large lagoon. Chocolate clay (CC) deposited in it. These currents were not linked to the littoral zone with wave activity, as granular composition of the deposits, their sorting and type of lamination are not peculiar to sediments of a coastal marine zone. They are characteristic of unidirectional currents with frequently changing velocities. Water from the lagoon flowed through the Manych passage into the Black Sea in the Late Khvalyn. Hence, last connection of the Caspian Black and Black Sea was at the end of the Late Khvalynian time (Early Holocene). At first, the water overflowed through the Manych passage (minimal width of 2 km) from the Caspian to the Black Sea; then, it reversed and flowed from the Black Sea to the Caspian Sea. At this time, when the most recent alluvial dam had not yet formed yet in Manych, there was infiltration of Cerastoderma glaucum to the Caspian Sea. Discusses the landforms similar to BK, in particular, the long ridges in the south of Western Siberia.