Glacier fluctuations since the global Last Glacial Maximum in the eastern Tanggula Mountains, China

Abstract

Distinct moraine complexes are well-preserved at the headwaters of the Requ River valley on the southern slope of Bujia Gangri, the largest center of modern glaciation in the eastern Tanggula Mountains in western China. Dating these moraines is an important step in understanding glacial history, palaeoclimate, and landscape evolution in this region. Surface exposure dating using 10Be was done on twenty-three rock samples from large granitic boulders embedded in moraine crests were collected from the Yongqu River valley and the Daxiong River valley, two glaciated valleys at the headwaters of the Requ River valley. The moraines (MW1 and ME1) closest to the current glaciers in the west (main) and east (hanging) valleys of the Yongqu River valley were dated to 203 ± 51 a (n = 4) and 162 ± 58 a (n = 3); the inner four end moraines (MW3–1) and outer ones (MW3–2) of the third moraine complex (MW3) in the main valley date to 16.8 ± 1.8 ka (n = 3) and 20.7 ± 1.3 ka (n = 2); end moraines (ME2) near the mouth of the east valley and a high lateral moraine (MEL) on its east side date to 18.9 ± 3.0 ka (n = 4); and a high lateral moraine in the Daxiong valley (MDXL) dates to 18.6 ± 1.3 ka (n = 3). The dating results indicate that these moraines were formed during the Little Ice Age (LIA), the Heinrich 1 (H1) event period, and the global Last Glacial Maximum (LGMG). These glacial events are synchronous with those across the Tibetan Plateau (TP) and its surrounding mountains. Combining the palaeoclimatic and palaeoenvironmental proxies in the TP and its surroundings, we infer that the cooling during the LIA, H1, and LGMG was a main control for these glacial advances.