青藏高原的末次冰期与最大冰期——对M.Kuhle的大冰盖假设的否定

M.Kuhle把青藏高原外缘山地的山麓泥石洪流堆积误认为冰碛,推算出高原上末次冰期雪线普遍比今降低1100-1500m,已低于高原平均高度,以此推断在青藏高原形成了统一大冰盖。本文根据中国学者大量的研究事实和确凿的冰川作用遗迹,重建冰期雪线分布高度,提出了“分散的山地冰川”的观点,并从古气候学和高原构造隆升等方面分析了原因,以此论证了“大冰盖说”的主观性。

Last Glaciation and Maximum Glaciation in Qinghai-Xizang Plateau--A Controversy to M. Kuhle Ice Sheet Hypothesis

Since the late 1950's, a lot of Chinese scientists explored the remain of Quaternary Glaciation in Qinghai-Xizang Plateau and its surrounding mountains, 3-4 glaciations were primarily recognized. The largest one occurred in late Middle Pleistocene with piedmont glaciers, ice caps and trellis valley glaciers in many high peak regions. But no evidences of unit ice sheet covered the whole plateau as described by M. Kuhle. Due to the further uplifting of the Himalayas and Qinghai-Xizang Plateau the climate become drier and drier, diminished the extension of glaciers during Late Pleistocene. The elevation of the snowline during last glaciation was about 4 000 m in south, east and northeast margins of the plateau and ascended to 5 500 in in northwest part of inland plateau. The thermal effect of the big plateau mass, the great increasing of aridity from southeast margin to northwest inland area and the abrupt decreasing of precipitation during Ice Age induce the distribution features of Quaternary glaciers in Qinghai and Xizang Plateau. The neglect of Chinese literature may be one cause of M. Kuhle's misinterpretation on the environment,of Quaternary Glaciations in Qinghai-Xizang Plateau.