Formation of proglacial dunes in front of the Puruogangri Icefield in the central Qinghai–Tibet Plateau: Implications for reconstructing paleoenvironmental changes since the Lateglacial

Abstract

There are sand dunes and stony desert surfaces (gobi) on the piedmont along the western side of the Puruogangri Icefield in central Qinghai–Tibet Plateau. The dunes formed on the gobi, probably after 16 ka. Their sediment derived from the underling till deflated by mid-latitude westerly winds and the Qiangtang high-pressure system. The gobi contains granitic moraine boulders, ventifacts of limestone and secondary CaCO 3 precipitates at subsurface. Occasional humus layers are present within the sand dunes. A total of 13 humus layers were collected for radiocarbon dating and 20 samples for particle size analysis. The dune particle size distribution is generally negatively skewed. The radiocarbon ages range from 12,709 to 922 calendar years BP. It is likely that the humus layers correspond to warm times and can be correlated to the results from oxygen isotopic data in the ice cores from Guliya in the western Kunlun Mountains and Dunde in the Qilian Mountains. These results initially provide an outline of Lateglacial climate history for the ice field area.