STUDY ON THE ICE AGE MIS₁₂ IN WESTERN CHINA

The dating is a very key problem in the study of Quaternary glaciation. Recent years, many technologies,for example,OSL (optically simulated luminescence),AMS (accelerating mass spectrometry), ESR (electron spin resonance) and so on, were used to date glacial deposits. Qilian Shan mounatains is the northeastern marginal mountains of the Qinghai-Tibetan Plateau and Tian Shan mountains is the big mountains in the center of Asia. The two mountains lie in the temperate arid region of Asia. However, because of appropriate precipitation in high attitude, there are a lot of contemporary glaciers in the two mountains. The glacial deposits and geomorphologies indicate that those glaciers occurred early and advanced for several times during Quaternary period. ESR technology was undertaken to define the timing of the glaciations and associated sediment deposition of the two mountains. The oldest moraine on the top of Zhonglianggan (2997m asl and 500m above the contemporary river level) in Bailang River Basin of Qilian Shan mountains was dated 462.9 ka BP. The oldest high Wafeng till (3450m asl and 250m above contemporary river level) of Urumqi River Basin, Tian Shan, was dated 477.1ka BP and 459.7ka BP.These datings show that the glaciers of the two mountains extended during marine isotopic stage 12(MIS₁₂) and implicate a response of the uplifted mountains to the global climatic deterioration.