The valley of the Absheron Volga was much wider than the valley of the modern river, its course lay several meters higher than the modern one. At the end of the Pliocene, the alignment of the relief of the Russian Plain was completed. The depth of the channel, the width of the river valleys, the thickness of the alluvium that filled them allow us to judge about the changes in the tectonic regime of the platform.
In the thickness of the earth's crust only the most deep channels are preserved. The long development of the rivers was completed by their sharp deepening in the middle Pliocene. This ended the first stage of their development. Submersion of the platform in the Late Pliocene led to the burial of river valleys. The development of the river network from the moment of its inception or renewal of the channel process in the buried or semi-buried valleys, to the new termination of the channel activity - the erosion cycle. Each cycle begins with a reinforced incision of the river and ends with the burial of its valley. During the first stage of the cycle, the channel deepens, most of the alluvium is carried to the lower reaches of the river and the receiving basin; the remaining low-power alluvium composes the enclosed low terraces. The deepening of the channel takes place in the conditions of a rising country. When immersed, during the second stage of the cycle, superimposed alluvium stratum accumulates in the valley, overlying the floodplain and terraces, the flow rate of the river decreases. River flow wanders around the created alluvial plain. At the end of the cycle, deep erosion is so reduced that the river turns into a chain of lakes, in some cases, the sea transgression into the valley leads to an interruption of the erosion cycle. This is exactly what happened in the Late Pliocene. Erosion cycles coincide with tectonic ones. The formation of extensive alluvial and marine plains, which buried completely deep valleys, ended the Pliocene cycle. The general uplift of the Russian platform at the border of the Quaternary period determined the beginning of a new erosion cycle. A new deepening of the channel took place in the Pliocene and more ancient rocks. The deep early Quaternary channels, like the Pliocene ones, are completely buried under the thick layer of the Middle Quaternary sediments accumulated in the conditions of the submerged platform. The quaternary erosion cycle has been completed. The new cycle, due to the raising of the platform, which began in the Late Pleistocene, is reflected in the first stage by deepening the beds and the formation of the enclosed terraces of modern river valleys. In connection with the continuing deepening of the channel, this cycle can be called modern. Cyprus Escort for booking. Visit our catalog of Escorts Cyprus Girls. Escort in Limassol, Larnaca Escort, Ayia Napa Escort, Paphos Escort and Escorts Nicosia. Choose Escorts and Call girls, erotic models, elite companions in Cyprus. Incall and outcall services by experienced providers. http://cyprusescort.com Are you bored alone? Do you want to feel the warmth of sexual female body without commitment? Or are you seeking beautiful and educated companion for a business meeting or leisure trip? Escort in Cyprus is the best choice for real men.
View the Top, Frequently Viewed Products
|
ee0793ffd7917edb19dd82275c3abb2b |
