Hydrogeological systems of landslides in central part of the Volga-Ural region

Abstract

Abstract The study of landslide massifs made it possible to identify two types of hydrogeological systems that differ by feeding area structure and transit zone. In landslide bodies of Urzhuminan stage, composed by dolomites and marls, hydrogeological systems are simple stratal. The aquifers are localized in fractured marls, which, under the influence of infiltration water seeping through them, have turned into a poorly structured gruss-rock cover, which lies on dense dolomites - water-resistant. The inclined bedding of dolomite layers creates the prerequisites for directed filtration of groundwater towards natural lowering. Here forming areas of ground water discharge as low-water springs. In landslides composed of the Upper Jurassic series clays and marls, hydrogeological systems are distinguished by the prevailing vertical groundwater infiltration in transit zone. Theirs’s water source is shallow lakes formed on the surfaces of landslide terraces. Under water pressure influence of in the lake basins and gravity, infiltration groundwaters leaking through the systems of cracks in clays penetrate to a more dense clay layers which are fluid trap. Here, directly under the lake basin, a dome of groundwater is formed. The flow of groundwater from the dome towards inclined depressions leads to creation of unloading areas. They are presented by permanently wet land (flarks) or low-water infiltration springs that come to the surface at the same hypsometric level.