Quaternary glacial geomorphology and glaciations of Kongur Mountain, eastern Pamir, China

Abstract

Kongur Mountain is the largest center of modern glaciation on the Pamir Plateau. During the glacial-interglacial cycles of the Quaternary, Kongur Mountain was extensively and repeatedly glaciated, and the glacial landforms from multiple glaciations are well-preserved in valleys, in basins, and on the piedmonts. Dating samples have been collected according to the distribution and weathering of the glacial tills, the relationship among the glacial deposits, and the loess or soil developed on the moraines. Electron spin resonance (ESR) dating of the samples was done using the germanium (Ge) centers in the glacial quartz grains, which are sensitive to both sunlight and grinding. The ages of the glacial deposits can be divided into four clusters, i.e., 13.1±0.8–27.0±2.2, 36.4±3.3–48.7±5.7, 65.6±6.8–86.6±8.9, and 105.6±9.4–178.3±17.8 ka. Six glacial advances in this region have been confirmed, which are equivalent in age to the Little Ice Age (LIA), Neoglaciation, marine oxygen isotope stages (MIS) 2, mid-MIS3, MIS4, and MIS6. The largest local last glacial maximum (LGML) occurred during MIS4 rather than the global Last Glacial Maximum (LGMG) of MIS2, and a glacial advance that occurred during mid-MIS3 was also larger than the LGMG. Furthermore, deeply weathered tills below 3500 m a.s.l. on the western slope of Kongur Mountain, when compared with the ages of the oldest glaciation of the Muztag Ata region, likely occurred prior to the penultimate glacial cycle. The glacial landforms prior to the penultimate glacial cycle on the northern slope are not well-preserved due to erosion after deposition. Several glacial deposits are only speculated to be distributed at higher elevations on the southwest side of the Gaizi Checkpoint. The extensive hummocky moraines on the western slope were formed by multiple glacial advances, and the latest glacial advance corresponded to mid-MIS3.