黄河源区早更新世含植物化石地层的发现及意义

通过对扎根加陇早更新世湖相地层(1919.6kaB.P.)、棒咯涌K5号钻孔早更新世河湖相地层(1135.9～945.4kaB.P.)、野牛河西岸早更新世河湖相地层(1548.2～765.4kaB.P.)以及产于扎根加陇早更新世湖相地层中的植物化石、各剖面孢粉资料的分析,获知黄河源区早更新世早期为亚热带山地针叶林植被景观,地层中木本植物花粉占绝对优势,以针叶植物云杉属、松属、冷杉属、铁杉属为主,是源区动植物发育的鼎盛时期;进入早更新世晚期初,乔木植物花粉迅速减少乃至全部消失,草本植物花粉大幅度增加。晚期末,孢粉出现贫化,以草本植物花粉为主,呈现荒漠草原植被景观。提出了现今黄河源区生态地质环境的形成是地质演化的必然结果。

Discovery of early Pleistocene strata containing plants fossils in the source area of the Yellow River and significance

The authors analyzed early Pleistocene lacustrine strata at Zhagenjialong (1919.6 ka B.P.), in borehole K5 (1135.9 945.4 ka B.P.) and on the west bank of the Yeniu River (1548.2-765.4 ka B.P.) and fossil plants and sporopollen data in various section in early Pleistocene lacustrine strata at Zhagenjialong. The analytic results show that in the early part of the early Pleistocene there occurred a subtropical hilly coniferous forest vegetation landscape in the source area of the Yellow River, and that in the strata woody plants predominate, mainly including needle leaf plants such as Picea, Pinus, Abies and Tsuga, indicating a flourishing period of animal and plant growth in the source area. At the beginning of the late Early Pleistocene, pollen of arborous plants was rapidly reduced and even all disappeared, and pollen of herbaceous plants increased significantly. At the end of the late part, sporopollen was diluted, with pollen of herbaceous plants predominating, showing a landscape of desert steppe vegetation. The formation of the present eco-geological environment in the source area of the Yellow River is the inevitable result of geological evolution.