The Pliocene-Quaternary history of mountain valleys in Central Asia and the problem of their age

Abstract

A close scrutiny of a great body of information on the stratigraphy of old alluvium and associated sediments permits to trace their connection with the morphostructural evolution of the region. A sequence of morphocycles of dominant erosion and alluviation have been identified in mountain valleys. The most important feature of the mountain valleys evolution throughout the Pliocene and Quaternary has been a complicated (though unidirectional) intermittent downcutting, with some elements of reciprocation; it manifests itself both in short and longer periods of the valley evolution. Intervals of fast and large-scale removal of debris from the mountains followed long periods of coarse deposits accumulation in the region's interior. The main cause of the debris ejection was the climate aridization.