Evidence of ancient rock-ice avalanches along the China-Bhutan Chomolhari Range,and their implications for demise of the summit  

作　　者：HU Kaiheng ZHANG Qiyuan LI Pu ZHANG Xiaopeng LIU Shuang LI Hao 

机构地区：[1]Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610299,China [2]University of Chinese Academy of Sciences,Beijing 100149,China

出　　处：《Journal of Mountain Science》2024年第9期2876-2890,共15页山地科学学报（英文）

基　　金：funded by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0902);the National Natural Science Foundation of China(91747207,41790434)。

摘　　要：Large-scale rock-ice avalanches resulting from the interaction of tectonics and climate are characterized with high mobility,huge volumes of sediment,and rapid denudation,being a major agent of landscape evolution in high altitude mountainous regions.Specifically,the extreme glaciated slope failures often transform into extraordinarily large and mobile debris flows,resulting in disastrous consequences such as sedimentation and desertification.Due to a dearth of on-site observation data and experimental data collection,our comprehension of the geomorphic and kinematic characteristics of rock-ice avalanches remains poor.Here we report a cluster of ancient rock-ice avalanches spreading along the Chomolhari range of the China-Bhutan Himalayas.By integrating remote sensing image interpretation with detailed field investigations,we demonstrate the geomorphic and sedimentary characteristics of four events among the avalanches.The estimated volumes of the four are 23.73 Mm³,39.69 Mm³,38.43 Mm³,and 38.25 Mm³,respectively.The presence of pre-existing moraines or alluvial fans constrained their movement,resulting in deposition features such as marginal digitated lobes at higher elevations and large depressed areas in the interior.Applying the Savage-Hutter theory,we calculate the basal friction angle and travel angle of these ancient rock-ice avalanches that are both less than 10°,affirming the similarity of these avalanches in the study area to those occurring in other regions.Our study significantly contributes to understanding the geomorphic and kinematic characteristics of rock-ice avalanches in high-altitude mountainous regions,providing valuable insights into their response to the disproportionate growth of Himalayan peaks.

关 键 词：Rock-ice avalanche HIMALAYAS Southern Yadong-Gulu rift Vertical slip-rate Landscape evolution 

分 类 号：P343.6[天文地球—水文科学] P542[天文地球—地球物理学]