ДОЛИННЫЕ ПЕДИМЕНТЫ В СРЕДНЕМ ТЕЧЕНИИ р. ОКИ

Large portion of steep bedrock slopes of the Oka river in the Ryazan region is occupied by extensive pediments 50–300 m width and 8–30° inclination. They are formed as a result of landslide occurring on the bedrock slopes composed of Neogene-Quaternary permeable sediments of 40 m depth underlain by confining layer of Jurassic clays. Groundwater discharge over the Jurassic clays provokes the insequent landslides, followed by the slope retreat into the interfluve areas, and by the formation of slightly dipping surface of the pediment. Denudation of valley pediments occurs mainly due to landslides moving over their surface. The width of valley pediments depends on the depth of Neogenе-Quaternary sediments and hypsometry of the Jurassic clays roof. The progressing erosive segmentation of the bedrock slopes prevents further sliding and widening of the pediments.