Rock glaciers in the Gangdise Mountains, southern Tibetan Plateau: Morphology and controlling factors

Abstract

Rock glaciers are linked to palaeoenvironment, water storage, sediment transport, and natural hazards. Previous rock glacier studies have been conducted in many places globally, but detailed studies have not been done in the Gangdise Mountains of the southern Tibetan Plateau (TP). In this study, 132 rock glaciers were mapped in the western, central, and eastern sectors of the Gangdise Mountains and their metrics calculated. The smallest rock glacier length in the east and the increasing trends of rock glacier density and specific area eastward reflect the effect of temperature and precipitation. The decreasing trend of mean altitude and minimum altitude of the rock glacier front towards east highlight the role of precipitation. Rock glaciers with altitudes of 5143–5651 m above sea level (asl) tend to face N, but their vector strength values decrease with altitude. Rising above 5651 m asl, rock glaciers tend to face SE. These results imply the ability of high altitude to promote rock glacier development on climatically unfavourable slopes. Bedrocks that mainly produce finer or platy debris are rarely sources of rock glacier materials. High altitude may diminish this effect. Aspect does not affect rock glacier size and shape, but rock glaciers on northern slopes have lower altitudes than those on southern slopes due to the effect of solar radiation. Welch’s test shows that rock glacier size is mainly controlled by non-lithological factors. By comparing with the previous results of the TP, it is found that increasing temperature and precipitation increase rock glacier occurrence but limit its size.