第四纪中国自然环境变迁的原因机制

作者在重建晚第三纪和第四纪古气候环境的基础上,着重讨论了晚第三纪和第四纪古气候之间的显著差异以及引起中国第四纪自然环境大幅度变迁的主要原因机制。中国新生代晚期构造运动导致自然环境的巨大变迁,其中青藏高原隆起的影响尤为突出。作者认为,青藏高原隆起及其反馈作用、季风环流的加强以及全球气候变化的影响,协同成为中国第四纪气候大幅度变化的主要原因,当然也是新生代晚期以来,尤其是中更新世以来中国自然环境变迁的主要原因机制。

THE CAUSAL MECHANISM OF QUATERNARY ENVIRONMENTAL CHANGES IN CHINA

The Late Tertiary and Quaternary palaeoclimates have been reconstructed and compared. In this paper we have also discussed the striking differences between them and the mechanism which caused a larger range of climatic changes in the Quaternary. The late cenozoic tectonic movement caused great environmental changes in China. The uplifting of Qinghai-Xizang (Tibetan) Plateau is the most important event. The uplifting began in Late Tertiary and proceeded violently in Middle Pleistocene with sequences of phased uplifts continuing up to the present day. Many of the present plateaux and high mountains in Northwest and Southwest China have been uplifted and consequently the configuration of the major relief of China being formed. The upheaval of so vast an area as Qinghai-Xizang Plateau is the main cause for the touching off of monsoon circulation and caused a far-reaching effect on climatic environments of China and its adjecent areas. During the Quaternary the plateau has been uplifted from 1,000 to 4,000—4,500m, with more vigorous speed of uplifting since the Middle Pleistocene (around 0.9 Ma B. P.). Evidences from different lines of research have shown that a considerable shifting of the climatic belts have taken place since the Middle Pleistocene. The feedback processes of uplifting of the Qinghai-Xizang Plateau and the strengthening of monsoon circulation have been the main causal mechanism for larger range of Quaternary climate variations in China.