巴颜喀拉山第四纪冰川序列

Study on the Sequences of the Quaternary Glaciations in the Bavan Har Mountains

巴颜喀拉山更新世期间曾发生过四次规模不同的冰川作用。分别代表末次冰期的两个阶段及倒数第二次冰期和倒数第三次冰期。末次冰期晚期冰川只发育在巴颜喀拉山主脊线附近，早期扩展到山麓地带。倒数第二次冰期为大型冰帽或小冰盖，巴颜喀拉山南北各６０ｋｍ的清水河、野马滩保存着这期冰期的大量冰碛与漂砾。倒数第三次冰期时，冰川规模最大，面积约达８００００ｋｍ￣２。根据覆盖地点及范围，我们提出末次冰期的巴颜喀拉阶段、尕拉拉海阶段、野马滩冰期与黄河冰期几个冰期概念。

Four periods of Quaternary glaciations in the Pleistocene have been found in Bayan HarMountains．They represent respectively the two stages of the Last Ice Age，the Penultimate iceage and the third ice age from the last．In the late stage of the Last Glaciation，the glacier de-veloped only near the mountain ridges of the Bayan Har Mts．，and in the early stage， the gla-ciers expended down to the pedimont of the Bayan Har Mountains．In the Penultimate IceAge，a great ice cover appeared and left a large scale till deposits and erratics，which weretransported 60km far from Bayan Har peak to Qingshuihe town in the south side and toYematan in the north side. The granite erratics was distributed over high positions such asChalaping Ridge.The area of the ice cover was probably up to 50 000km^2. Further more，manv evidences including glacial landforms and sediments seems to show that a more exten-sive ice cover existed in this area with glaciated area of about 80 000km^2 in earlier time，maybe in the third ice age from the last．The scale of glaciation is quite different in landforms from the other areas in the Tibetan Plateau， It covered the source area of the Yellow River from Xingsuhai in the west to Duogerongtan in the east，incuding Gyaring and Ngorin lakes.Based on the scales and the sites of the glaciations，the ice ages can be named as Bayan Har stage and Galalahai stage of the Last Ice Age，Yematan Ice Age and Huanghe Ice Age.