Badyukova E.N.

Moscow State University, Moscow, Vorobievy gori, Geographical Department, E-mail: badyukova@yandex.ru

Many researches propose that the age of chocolate clays (CC) is Early Khvalynian. That time Caspian Sea level rose up to +50 m, but chocolate clays have been recorded at the depth of -80 m, i.e. CC are the deepwater sediments. In our opinion CC accumulated in shallow lagoons under the Barrier Islands protection.

A geomorphologic analysis of CC distribution, absolute dating of mollusk shells (C¹⁴) from these and other sediments allow to suppose that the radiocarbon dating from the Northern Caspian Sea, Volga delta and adjacent areas gave more or less reliable results, according to which the age of the Khvalynian transgression is about 11–20 Ky BP. However, this is not the age of the maximum of transgression but only age of its final trangressive-regressive stage, i.e. the Late Khvalynian transgression. We assume that the age of the high terraces formed during the maximum of Early Khvalynian transgression is older – 40–70 Ky BP.

Keywords: Volga delta, chocolate clays, lithology, sea level oscillations, lagoon-transgressive terraces, Khvalyn transgressions, Baery knolls