ИСТИНА

Many geological sections in the ledge of the Lower Volga valley have been actively studied since the end of the 19th century. Results many years of field work showed that in all the studied quaternary sections along the Lower Volga valley alluvial sediments of the Khvalynian time (end of the late Pleistocene - early Holocene) are absent. Numerous literatures, descriptions of wells, maps were used as research methods. We conduct geomophological mapping out in Arcgis using the SRTM DEM and studied many outcrops along Volga valley and in the Baer knolls – gyant underwater dunes of the Northern Caspian. We consider the Volga River probably did not flow at the site of its present position in the Khvalynian time. In this regard, the question arises of where the Volga channel was located in the North-Western Caspian in the Khvalynian time. Thus, we propose the extreme western branch of the Volga ran along the foot of the Eastern Ergeni slopes, eroded the surface of the marine plain, as a result of which the Sarpinsko-Davanskaya hollow was formed, the eastern branches of the delta flowed into the Kha-ki saline. Which was one of the estuaries of the Northern Caspian, where the waters of one of the extreme eastern channels of the PaleoVolga stream probably flowed into. In the Khvalynian time, the Volga channel in the lower reaches had multiple terminal distributary channels at different scales. Where were arcuate fluvial-dominated delta much larger (200-210 km wide) than the modern delta and somewhat reminiscent of the modern Lena delta in size. In the location of the modern Volga-Akhtuba floodplain there was probably a small central branch, in the west there was a Sarpinsky branch, and in the east, there was an Elton-Khaki branch. They were interconnected by an extensive system of branches, the relief of which is still preserved. At the very end of the late Khvalynian time, the Sarpa and Khaki branches began to die off, and most of the water began to rush along the central branch, forming the modern Volga-Akhtuba valley.