DISSECTED ROCKSLIDE AND ROCK AVALANCHE DEPOSITS; TIEN SHAN, KYRGYZSTAN

摘要

Rockslides and rock avalanches in Northern and Central Tien Shan, that have been deeply dissected by subsequent erosion, or which internal structure was studied in trenches and road cuts, are described, Presence of intensively comminuted debris overlaid by coarse blocky material is found out in most of the case studies. At those cases, where different types of parent rocks outcrop in the rockslide scars, the resultant deposits are composed of the unmixed 'layers' of debris originated from these rock types. Such grain size distribution and unmixing of debris can be considered as typical features of large-scale massive rock slope failures. Basal sliding surfaces with different relationships between rockslide debris and underlying soil can be observed at several sites. Comprehensive study of deeply dissected deposits of rockslides and rock avalanches can shed light on mechanism of their rapid motion and of 'rock' -"'debris' transformation.