Scientific contribution of G.I. Rychagov to the study of the Caspian Sea and its' basin

Based on many years of geomorphological studies over the coast of the largest lake in the world, the outstanding Russian geomorphologist G.I. Rychagov formulated the idea of the Caspian Sea as a complex self-regulating system in which the altitude position of the basin level is determined not only by the values of the components of the water balance, but also by the topography of the bottom and the land adjacent to its' water area. Regarding the modern (Holocene) stage of its' development, the author determined the amplitude of level fluctuations in the range of absolute values from –25 to –30 m. The long-term forecast for the development of the Caspian Sea level was justified twice during the author’s lifetime. The experience of paleogeographical studies of the Caspian coast allowed G.I. Rychagov to formulate and solve a number of scientific and methodological issues. First of all, it showed the high information content of geomorphological data and geomorphological analysis in paleogeographical and forecasting work. Thus, data on the depths of incision of the mouth areas of the valleys of small rivers flowing into the Caspian Sea, in addition to the heights of the surfaces of the Neo-Caspian marine terraces, turned out to be excellent indicators of the magnitude of sea level fluctuations. The close connection between the development of the Caspian Sea and the processes in its' basin required a detailed study of its' largest part – the Volga River basin. The key site here was the Satinsky educational and scientific polygon in the basin of the middle reaches of the Protva River. Many years of comprehensive work under the leadership of G.I. Rychagov made the Satinsky polygon one of the most studied geologically and geomorphologically in the central region of the East European Plain. The geomorphological and complex paleogeographical method of studying the relief of the territory and the Middle-Upper Neopleistocene strata composing it allow us to consider the test site as a stratotypic area for the Middle Neopleistocene of the region. The independence of two glaciations of the Middle Neopleistocene – Moscow and Dnieper – was shown.