青藏高原隆升过程与环境变化

Environment Change and Uplift of Qinghai-Tibetan Plateau

根据近期研究成果 ,陆陆碰撞的初期发生在为 60～ 65Ma ,但此时青藏高原并未发生大幅度的隆升。而在此后的 3 7～ 3 .6Ma期间 ,青藏地区经过两次隆升与两次夷平 ,形成了目前高原及其周缘山地广泛分布的两级夷平面 (山顶面与主夷平面 )。其中山顶面形成于渐新世 ;主夷平面形成于新第三纪 ,结束于 3 .6Ma ,当时海拔不超过 1 0 0 0m。所以青藏高原的形成是多期脉动性隆升的结果。综合新生代以来全球性重大的构造气候事件 ,可以发现它们与青藏高原隆升历史具有良好的时间耦合性。

The collision between the Indian and Eurasian Plates during 60～40 Ma ago resulted in the complete closure of the Tethys and the formation of Qinghai-Tibetan Plateau as a continent, but the altitude of the surface was very low in the period. At present, there are two planation surfaces (Summit Surface and Main Surface) in the Qinghai-Tibetan Plateau. The Summit Surface had been formed in Oligocene and early Miocene, and the Main Surface was formed during 7～3.6 Ma B.P. Then its height was lower than (1 000) m a.s.l. Breaking up of the Main Surface at 3.6 Ma B.P. indicates the beginning of intense rise of the Qinghai-Tibetan Plateau. This infers the uplift of Qinghai-Tibetan Plateau is multistage, heterogeneous. A good corresponding relationship between the occurrences of important climatic changes and the intense tectonic movements of the Qinhai-Tibetan Plateau in the Cenozoic implies that they are closely linked. It is possible that the uplift of the Qinghai-Tibetan Plateau was one of the important factors controlling the climatic change in the Cenozoic.