Morphological characteristics and factors influencing ice-free cirques in the Qilian Mountains

Abstract Cirques are classic glacial erosion landforms, and studying their morphological development provides valuable paleoclimatic and paleoenvironmental insights. However, research on cirques on the Tibetan Plateau and surrounding mountain ranges has focused primarily on the southern, eastern, and northwestern plateau, with limited attention given to the northeastern region, hindering comparative analyses between different regions. In this study, 1132 ice-free cirques in the Qilian Mountains on the northeastern edge of the Tibetan Plateau are examined, and their spatial distribution patterns and influential factors are analyzed. The results show that the cirques’ aspect in the Qilian Mountains is predominantly north-facing. Influenced by climate and lithology, the size of the cirques gradually increases from east to west, and the elevation parameters of the cirques are significantly affected by aspect.. The cirques in the western section are shaped primarily by lateral erosion, whereas those in the central section experience more balanced erosion, and those in the eastern section are controlled primarily by longitudinal erosion. A comparison with existing cirque morphological data from other regions of the Tibetan Plateau and surrounding mountain ranges reveals that the formation of cirques is affected by both climatic and non-climatic factors, and their formation ages are difficult to determine.