Cirques in the eastern Kunlun Mountains, NE Tibetan Plateau and their links to climatic and non-climatic factors

Abstract

Cirque metrics are widely used to deduce palaeoclimate conditions, with extensive research in the alpine regions of High Mountain Asia (HMA). Some debates remain regarding the relationship between cirque morphology and climate/topography and a detailed study is needed to deepen the knowledge of cirque development. This study delineated and analysed 375 cirques in the eastern Kunlun Mountains, northeastern Tibetan Plateau. Results show that cirque area and development degree decrease from west to east. Cirques and modern glaciers predominantly face north. In an east–west contrast, more cirques face west, with lower cirque floor altitude (CFA) than those facing east, highlighting the effect of the east Asian monsoon (EAM). The eastward decline in CFA in the eastern Kunlun Mountains implies that the palaeoprecipitation increases eastward, highlighting the dominant role of the EAM on glaciation during the last glacial period. The lower aspect asymmetry of the cirques than that of the modern glaciers implies greater glacial coverage during the last glacial period than today. By comparing the results across the HMA, it is suggested that cirque density, specific area, size, floor altitude and aspect asymmetry exhibit no distinct correlation with annual temperature, precipitation, altitude and bedrock resistance. Cirque development depends on the relative efficacy of glacial erosion, which is jointly controlled by local climate, topography and bedrock type, which may be regionally diverse. This may be an explanation for the inconsistencies in the relationships between cirque metrics and climate in different regions.