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.

A generalization of the materials of a comprehensive paleogeographic study in the ancient glacial region of the Russian Plain is aimed at establishing regional features of the geomorphological structure and patterns of spatial variability of indicators. For these purposes, geological and geomorphological zoning of the territory was carried out on the basis of a systematic approach and under the control of paleogeographic expertise. On the compiled map, the territorial divisions are highlighted: against the background of different age paleogeographic zones, 4 geological provinces and 14 geologic-geomorphological regions are distinguished. Their complex characteristics are obtained by the totality of the leading geomorphological processes. Particular attention is paid to the study of the glacial relief, which plays an important role in paleogeographic reconstructions of this area. Marginal zones infrastructure of the ice sheets of different ages has been studied in detail, which makes it possible to make more exact the maximum and stadial boundaries of the Moscow and Kalinin ice sheets. Thus, regional features of the structure and composition of the morpholithogenic basis of landscapes are established. The laws of its formation are confirmed: geological and geomorphological heredity and paleogeographic conditionality. The study of regional features of the geomorphological structure of the ancient glacial region makes a significant contribution to the reconstruction of the glacial rhythm of the Pleistocene. The results of integrated geologic-geomorphological zoning facilitate the regional targeted estimation of the state of geoecological stability of geosystems and make it more justified.

The 100-km long upper reach of the Volga River between the Selizharovo and Zubtsov towns is oriented opposite the Late Valdai ice sheet which covered the Volga River sources, i.e. the area of the Verkhnevolzhskiye Lakes, during the Last Glacial Maximum (LGM), about twenty thousand years ago. Due to the Glacial Isostatic Adjustment (GIA), crustal subsidence occurred in the progalcial area and further from the ice sheet a compensational rise was formed towards which the Volga River valley was directed. The study is aimed at the investigation of the influence of GIA-induced changes in gradients during MIS 2 and the Holocene on the evolution of the Volga River valley. At the key site near the Bolshaya Kosha village (Selizharovo district, the Tver Oblast) it was found that prior the LGM the alluvial aggradation in the valley was most probably associated with the decrease of valley gradient because of the GIA-induced formation of a crustal proglacial flexure. However, the total depth of subsidence was not enough to completely stop the Volga River flow and promote the formation of a proglacial lake. During the LGM the highest (third) and widest river terrace was formed by both river and glacial melt waters. After the LGM the river incision resulted in the formation of a terrace staircase. The incision was caused by the increase of valley gradient due to the glacio-isostatic uplift of the proglacial area in the process of deglaciation. The incision was over in the Mid-Holocene (about 6 kyr BP). The total depth of incision was 15 m and the average incision rate was about 1 mm/year.

The 100-km long upper reach of the Volga River between the Selizharovo and Zubtsov towns is oriented opposite the Late Valdai ice sheet which covered the Volga River sources, i.e. the area of the Verkhnevolzhskiye Lakes, during the Last Glacial Maximum (LGM), about twenty thousand years ago. Due to the Glacial Isostatic Adjustment (GIA), crustal subsidence occurred in the progalcial area and further from the ice sheet a compensational rise was formed towards which the Volga River valley was directed. The study is aimed at the investigation of the influence of GIA-induced changes in gradients during MIS 2 and the Holocene on the evolution of the Volga River valley. At the key site near the Bolshaya Kosha village (Selizharovo district, the Tver Oblast) it was found that prior the LGM the alluvial aggradation in the valley was most probably associated with the decrease of valley gradient because of the GIA-induced formation of a crustal proglacial flexure. However, the total depth of subsidence was not enough to completely stop the Volga River flow and promote the formation of a proglacial lake. During the LGM the highest (third) and widest river terrace was formed by both river and glacial melt waters. After the LGM the river incision resulted in the formation of a terrace staircase. The incision was caused by the increase of valley gradient due to the glacio-isostatic uplift of the proglacial area in the process of deglaciation. The incision was over in the Mid-Holocene (about 6 kyr BP). The total depth of incision was 15 m and the average incision rate was about 1 mm/year.

Basing on the detailed integrated studies, the history of the Protva River valley development is considered. Specific features of the geological and geomorphologic structure of the differently aged terraces are established. The obtained lithologic-mineralogical and palynological characteristics of their alluvium are a reliable diagnostic and correlation criterion. The erosion-accumulative cycles of valley development were identified for the late Neopleistocene. Palynological data provided for the reconstruction of the landscape and climatic conditions of terracing, including the paleoclimatic rhythms of the late Neopleistocene, MIS5, MIS-4, MIS-3, MIS-2. The materials obtained make it possible to unequivocally speak of pronounced cooling in the central region of Russia during the Kalinin period, weaker in intensity than that of the Late Valday era of the Ostashkov Ice Age. The epochs of cooling are separated by the Middle Valday warming.

На основе комплексного палеогеографического анализа проведена реконструкция радиально-маргинальной структуры московского и калининского ледниковых покровов с использованием надежной стратиграфической основы и детальных геоморфологических построений. На составленной геоморфологической карте отражена инфраструктура краевых ледниковых образований разновозрастных зон. Подтверждается радиальная потоковая структура ледниковых покровов. Обоснована маргинальная структура и динамика стадиальных зон московского и калининского оледенений. Уточнены границы их максимального распространения в регионе. Установленные пространственные и временные закономерности развития ледниковой ритмики в центральном регионе Русской равнины имеют важное палеогеографическое значение. Based on a comprehensive paleogeographic analysis, the radial-marginal structure of the Moscow and Kalinin ice sheets was reconstructed using a reliable stratigraphic base and detailed geomorphological structures. The geomorphological map shows the infrastructure of the regional glacial formations of uneven age zones. Confirms the radial flow structure of the ice caps. The marginal structure and dynamics of the stadial zones of the Moscow and Kalinin glaciations are substantiated. The boundaries of their maximum distribution in the region are specified. The established spatial and temporal patterns of the development of glacial rhythms in the central region of the Russian Plain have an important paleogeographic significance.

On the basis of the complex lithological and geomorphological zonation, the features of morphosystem characteristics were revealed. Map was produced of morphostructural provinces, paleogeographical zones of different age glaciations, which were divided into 19 areas. The map legend contains specific geomorphological and lithological indicators of the regional morpholithosystems. As a result of the comparative analysis of the most important patterns of formation and trends of spatial variability characteristics the following issues were established: a) the provincial morphostructural and geological inheritance; b) paleogeographically preconditioned zonality of morphosculptures, types of sediment sequences and facial-genetic diversity; c) landscape and climate relations and regional particularities of exogenous processes in the relief transformation and sedimentation. The complex lithological-geomorphological zoning has high scientific and methodological value. The identified regional patterns and characteristics of morpholithosystems are relevant for reliable paleogeographic reconstruction and interregional correlations, as well as to assessment of the forecast and the state and prognosis of geo-environmental sustainability of the natural environment.

Проведено комплексное литолого-геоморфологическое районирование центра Русской равнины, на основании которого выявлены региональные характеристики морфолитосистем. Составлена карта территориальных подразделений морфолитоструктур на провинции и палеогеографические зоны. В легенде представлена сводка характерных геоморфологических и литологических показателей региональных морфолитосистем. В результате сравнительного анализа установлены важнейшие закономерности формирования и тенденции пространственной изменчивости характеристик: а) провинциальная морфоструктурная и геологическая унаследованность; б) палеогеографически обусловленная зональность морфоскульптур, типов строения разрезов и фациально-генетического разнообразия; в) ландшафтно-климатическая зависимость и региональная специфика экзогенных процессов рельефообразования и осадконакопления. Выявленные региональные закономерности и характерные черты развития морфолитосистем могут быть использованы при палеогеографических реконструкциях и межрегиональных корреляционных построениях, а также в целях оценки состояния и прогноза геоэкологической устойчивости природной среды.

Complex investigation of the peculiarities of landscape formation and sedimentation is an important component of regional paleogeographical reconstructions. The geomorphological and lithological maps compiled by the authors demonstrate the regularities of spatial differentiation and trends of age changeability of morpholitosystems. These trends served as the basis for mapping the paleogeographical zones of the East-European Plain with the history of regions’ development taking into account. The separation of the territory into paleogeographical zones, provinces, regions was fulfilled with the following estimation of landforms stability. Paleogeographical approach based on the purposive zoning gives the possibility of complex assessment of natural environment stability and regions of ecological risk. Paleogeographical expertise improves reliability of forecast for the morpholithosystems development in extreme situations.