Stages of river network formation of the Upper Kama River basin in the Pleistocene

Abstract

River network formation in the northeast part of the East European Plain was discussed. The relevance of the study is due to a lack of knowledge about the functioning and development of the Upper Kama River basin in the Pleistocene. Most of the available data quite schematically describe the scope and stages of the change in the direction of development of channel processes in space and time. The decoding of satellite images from the Landsat-8 OLI, SPOT-5 satellite for the period of 2014–2018 and the ESRI ArcGIS World Imagery open mapping service data were used as the main method for studying the structural features of the river network, meso- and microrelief, vegetation distribution, as well as the nature and degree of moisture of the Upper Kama River basin. For geomorphometric analysis, digital elevation models from freely available (ArcticDEM, Alos DEM, TanDEM-X) and created on the basis of vectorization of maps of scales 1: 100 000 and 1:25 000 were used. As a result, events of different scales were highlighted: inter-basin – the union or rupture of the basin of the western pra-Kama River with adjacent river systems (Vychegda, Vyatka); regional – breakthroughs of lake waters through the Kirsa–Veslyana and Urolka–Vishera watersheds, which formed a single Kama River valley from the source to the mouth of the Vishera River. The formation of the South Keltma River (the left tributary of the Kama River) can also be attributed to the regional level of events. This river, by its location, inherits the lower course of the pra-Kosa River, which still flowed north in the middle Pleistocene and belonged to the pra-Vychegda River basin. The local events include the formation of macrobends in the valleys of the tributaries of the pra-Kama River and the formation of the Late Pleistocene incisions of channel systems on the low terrace of the Kama River. The composition of the sediments (according to drilling data) and the geomorphological data clearly indicate the Late Pleistocene age of watercourses that developed here earlier. In the modern landscape, their channels are represented by an erosive microrelief preserved among the bog geosystems.

Keywords

• upper kama basin
• upper kama depression
• keltma hollow
• drainage network
• spillway
• pleistocene
• holocene
• radiocarbon dating
• remote sensing