Extensive glacial advances during the Last Glacial Maximum near the eastern Himalayan syntaxis

Abstract

Climatically, the eastern Himalaya are mainly controlled by the Indian Summer Monsoon (ISM) and important region for understanding the relationship between ISM and glacial change. This region is therefore useful for studies of the relation between glacial changes and ISM. Using a geomorpho-stratigraphic method combined with GIS, we investigated and mapped the outmost lateral-frontal moraine of the most extensive glaciations that occurred in the Basongcuo (BSC) catchment, near the eastern Himalayan syntaxis. Using optically stimulated luminescence (OSL) and 10Be surface exposure dating technique, we dated five boulders and 23 sediment samples. The resultant OSL and 10Be ages show that the region's glaciers were at their most extensive positions between ∼16 and 31 ka. Glacial coverage was 507.5 km2, 9.9 times greater than it is today (51.5 km2), with an equilibrium line altitude (ELA) depression of ∼690 m. The rapidity with which the Last Glacial Maximum (LGM) glacial advance and retreat occurred suggests that temperature was the dominant control on glacial change.