Aeolian Geomorphology and Environmental Evolution Around Puruogangri Ice Field, Tibetan Plateau
ZHANG Wei min, YAO Tan dong, LI Xiao ze, QU Jian jun, HAN Tian ding (Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhuo Gansu 730000, China)
Glacial abrasion, vast moraine deposits due to glacial retreat and frigid weather provide a mass of material for Aeolian deposits in the high and cold regions. Aeolian geomorphologic development is closely relating to high and cold environments. Dunes develop mainly in aggradation form because of congelation, resulting in huge crescent dunes. Migration and erosion of dunes mainly occurs in warm season. Migration of crescent dunes is very slow, with mean annual velocity of about 1.8 ～ 0.5 cm·a -1 , together with aggradation rate of about 0.3 ～ 0.08 cm·a -1 . Environmental evolution around the Purogangri Ice Field mainly depends on temperature condition. The dating of dune humus has a certain degree relation with the dating of ancient dunes in eastern deserts in China and the dating of Dunde Ice Core. So it can be seen that the intensity of southwest monsoon plays a very important role in this region. In view of formation mechanism of monsoon, change in underlying surface of the plateau results in difference in radiation, which is an important factor for the intensity of southwest monsoon and the change of temperature and precipitation in the hinterland of the plateau.