The Khvalyn stage in the history of the Caspian Sea
Data concerning the Khvalyn stage in the history of the Caspian Sea are analyzed and the conclusions are as follows. First, the majority of stratigraphic-paleogeographical schemes for that period of time are based on two methods, i.e. biostratigraphy and absolute geochronology. Second, application of <sup>14</sup>C and <sup>230</sup>TH/ <sup>234</sup>U methods for dating Khvalyn sediments from terrestrial samples cut down their age. This contradicts the paleogeographical events of that stage of the Caspian Sea evolution and distorts the schemes of correlation between the Caspian Sea transgressions and the glacial periods within the northern part of the East European Plain. Third, more reliable data on the paleogography of the Khvalyn stage could be obtained by using the geomorphologic analysis based on the investigation of particular material objects, i.e. relief and sediments, with due regard to the general eographical regularities.