中国西部MIS_(12)冰期研究

STUDY ON THE ICE AGE MIS_(12) IN WESTERN CHINA

祁连山摆浪河上游和天山乌鲁木齐河源是现代冰川和第四纪冰川活动的地方。我们运用ESR技术对第四纪冰碛进行测年研究 ,摆浪河上游最老的中梁赣冰碛为 462 9kaBP ;乌鲁木齐河源最老的上槽谷高望峰冰碛为 477 1kaBP和 459 7kaBP ,从而确认了中国西部山地冰川对全球化深海氧同位素 1 2阶段 (MIS12 )冰期的响应。

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(MIS 12) and implicate a response of the uplifted mountains to the global climatic deterioration.