Inherited depressional valleys in the Kazan' karst region

Abstract

The paper describes inherited depressional valleys formed by the karst and piping processes on the high Quaternary terraces of the Volga River near Kazan' city. The erosional network of the paleo-Volga initiated karstification of the underlying sulfate rocks dated to the Lower Permian. After the ancient valleys had been covered by Neogene and Quaternary deposits, the piping acted within the covering mantle over the karst zones, as a result, the ancient erosional network has been revealed on the present-day surface.