Timing and extent of glaciation in northern High-Mountain Asia during the Middle and Late Pleistocene

High-Mountain Asia (HMA) hosts the largest concentration of modern glaciers in middle- and low-latitude regions. The widespread glacial landforms in HMA suggest that these glaciers have experienced significant changes in extent over time. The climate of northern HMA is influenced mainly by the Asian monsoons and the mid-latitude westerlies. Changes in the climate system during glacial-interglacial cycles potentially resulted in a unique pattern of glacial evolution in northern HMA; however, elucidating this pattern requires a comprehensive understanding of the spatiotemporal evolution of the glaciers in this region. To achieve this, we compiled 450 ¹⁰Be exposure ages from northern HMA, including 84 new and 366 previously reported ages, and we also conducted high-resolution simulations of paleoglacier extent that correspond with glacial geological records. Our findings emphasize the complexity of past glacier evolution throughout HMA. The two climatic domains share similarities in glacial sequences, climatic mechanisms, glacial style, and depression of the equilibrium line altitude (ELA). Landforms created by glacier advances corresponding to Marine Isotope Stages (MIS) 6, 3, and 2 have been identified in both domains, indicating a strong relationship between these advances and cooler climatic conditions. Since the penultimate glaciation, glaciers in northern HMA have gradually evolved from extensive ice fields to piedmont glaciers, to valley glaciers, and then to cirque glaciers. This transformation is reflected in the progressive ascent of the ELA. A key difference in glacial evolution between these two climatic regions is that the timing of the local last glacial maximum (lLGM) was asynchronous compared to the global last glacial maximum (gLGM). The timing of the lLGM varied between the monsoons-westerlies transitional domain and the westerlies domain, occurring during MIS 3 and MIS 4, respectively. This difference was caused by variations in the relative strength of atmospheric circulation systems and changes in moisture supply. In a similarly cool climate, variations in precipitation distribution explain the differing patterns of ELA change observed in these two climate domains during past glacial cycles.