摘要
黄河源区盆地北面的扎日加山、布青山、阿尼玛卿山和南面的巴颜喀拉山，中更新世以来有３次大冰期，以倒数第三次冰川规模最大，形成４个大冰帽。中更新世开始，由于昆仑山的强烈隆起，盆地沉积中心由北向南迁移，形成了河源区下沉性湖泊群，堆积了厚数十米至两百多米的河湖相沉积。晚更新世末次冰期时湖水外泄，进入若尔盖盆地，黄河水系开始成为一体。全新世时黄河曲折东流。
The lake basin area in the source of the Yellow River is a tectonic depression zone since Neozonic. During the Tertiary, there was a typical high peneplain with a lot of hills and lower mountains of 500～1000 m a.s.l. In those years, the climate was warm and humid. There were a lot of karst features appeared on the limestone massif and red debris deposits in the piedmont, with large paleolakes. Up to the end of the Tertiary, the plateau uplifted and the climate turned to cold, but it was still a bigger lake basin during the early Pleistocene, and in the Xixiabangma Glaciation, no glacier developed in these mountains because the snowline altitude was over the altitude of the mountains. During the Cahaxili Glaciation of the middle Pleistocene, there were glaciers developing in the Bayan Har, Zarijia, Buqingshan and Anyemaqen Mountains and four big ice caps with a diameter of about 30～50 km. Up to the late stage of the middle Pleistocene, penultimate glaciation, glaciers extended downward to valleys and Ngoring Lake was a large glaciofluvial lake. Some lakes such as Xinxinhai Lake on the north slope of the Mianshaling range also appeared. During the last glaciation of the late Pleistocene, medium valley glaciers developing in the mountains and the climate was cold and dry with strong wind. In Mianshaling area the eolian sand deposited largely and the glaciofluvial lakes shrank, because the lake water outflowed eastwards owing to neotectonic fault with a direction of east-west. The Yellow River system became connected together and a large of water with sand from lake area of the source of the Yellow River run into the Zoige Lake area. In the middle of the Holocene, lake area greatly shrank and large lake bench and valley plain with a dry grassland appeared, and meanders in the Yellow River were developing.
出处
《冰川冻土》
CSCD
北大核心
1996年第3期210-218,共9页
Journal of Glaciology and Geocryology
关键词
古冰川
古环境
黄河源区
Spaleoglacier, Paleoenvironment, source area of Yellow River
