Modern morphodynamics of high mountain periglacial slopes, Río Cachapoal basin, Central Chile

Types of slopes and correlative basal deposits are studied in an Andean high valley of Central Chile, considering the slope sediment potential supply and its stability conditions. The morphotectonic dominion is characterized by detritic-volcanic and sedimentary formations, continental and marine, which appeared

high affected by tectonic forces and strongly folded. Consequently, the slopes are analyzed like systems related to the folded structure, with variations both by the style and the arrangement of the layers in a monocline structure. The slopes basal fonns correspond to colluvial cones and talus, in different states of relative stabilization by vegetation. Only in the middle and higher parts of the valley, loose and consolidated pure gravitational deposits are observed. The differences founded in the present conditions of slope deposits, could be explained by the altitudinal differences and by the high level of faulting and folding of the rock layers, without to find a clear relation with the lithological composition. At the present, active avalanche processes dissect, reactivate and reworkthe basal deposits with a strong seasonal dynamics.