STUDY ON THE DEVELOPMENTAL CHARACTERISTIC, EVOLUTION PROCESSES AND FORMING MECHANISM OF XIAZANGTAN SUPER LARGE-SCALE LANDSLIDE OF THE UPPER REACHES OF YELLOW RIVER

The developmental characteristics, formation mechanism and evolution process of the Xiazangtan ancient super large scale landslide located at the upper reaches of Yellow River is a typical and representative case in the Jianzha Basin, northeast Tibet Plateau of China. In this paper, through meticulous field surveys, geological exploration, laboratory testing, and remote sensing interpretation and other ways to carry out the developmental characteristics, moving regions, evolution process and formation mechanism of this landslide, and mainly achieved the following conclusions: 1) There are two developmental stages of Xiazangtan super large scale landslide, and the first stage occurred about 50kaBP with whole volume of about 14.56 × 10⁸m³ and sliding distance was 8.16km, the surface plane likes arm-chair type with the moving speed of 66.11m/s in the back sheering crack opening, therefore, the first stage is a high-speed long run-out landslide. The second stage occurred about 30kaBP and belonged to the disintegration landslide in front of the first stage. 2) There were four phases in the Xiazangtan landslide forming processes, they are ancient landslide deforming and failing phase, the first stage of landslide occurred and the landslide lake formed in the back mass, the second stage of landslide happened and the landslide disappeared. 3) The first stage of Xiazangtan landslide controlled by the warm and humid climate change on rainfall in the 50kaBP and Suozi landslide drawdown of damming lake water level located also the Jiazhan Basin, and the second stage was triggered by the highly precipitation in the Marine Isotope Stage 3a.