东、西昆仑山晚新生代以来构造隆升作用对比

东、西昆仑晚新生代以来隆升过程和程度存在明显差异。东昆仑山现代地貌格局主要是在第四纪以来经过早中更新世之交的昆黄运动和中更新世晚期的共和运动形成的,山系的崛起在时空演化上呈现出由北向南的迁移趋势,而西昆仑山在第三纪已有明显的地貌反差,第四纪地貌反差加剧。东昆仑地区在昆黄运动后尽管形成了近东西向的东流水系,但向南的强烈溯源侵蚀并奠定现代河流水系格局主要发生于中更新世晚期,与共和运动大体同时,而西昆仑地区向南的强烈溯源侵蚀主要发生于早更新世晚期,与东昆仑的昆—黄运动大体同时。在剥蚀程度上,东昆仑最上部3km的去顶至少延续了45Ma,而西昆仑公格尔—塔什库尔干地貌单元只延续了2~5Ma。控制东、西昆仑晚新生代构造隆升的动力背景可能取决于强烈加厚及强烈隆升的青藏高原岩石圈边缘的重力伸展垮塌与来自南部的挤压应力之间的动态平衡。考察青藏高原隆升过程与机制,不仅要注意隆升作用的共性,更要强调不同部位隆升过程及动力学的差异性。

Comparing of the tectonic uplift since Late Cenozoic between the East and West Kunlun Mountains

There is obvious differentia of the uplift processes during the I.ate Cenozoic between the East and West Kunlun Mountains. The modern relief framework of the East Kunlun Mountains was mainly built in Quaternary, by the Kunlun-Yellow River Movement in late Early Pleistocene and the Gonghe Movement in late Middle Pleistocene. It also can be detected in the East Kunlun that the development of the mountains transferred from north to south. The West Kunlun Mountains, however, began to build in Tertiary and prick up to uplift in Quaternary. Although an eastward flowing drainage system in the East Kunlun was formed after the Kunlun-Yellow River Movement, the modern drainage system was mainly formed in late Middle Pleistocene by strong southward tracing to the source eroding, contemporary to the Gonghe Movement. The West Kunlun, however, strong southward tracing to the source eroding was mainly occurred in late Early Pleistocene, basically contemporary to the Kunlun-Yellow River Movement. The unroofing of the upper 3km rocks in the East Kunlun Mountains lasted about 45 Ma at least, but only 2~5 Ma in some part of the West Kunlun Mountains. The dynamics controlling the tectonic uplift of the Kunlun Mountains may depend on the balance between the gravity collapse of the thicken lithosphere of the edge of the Tibetan Plateau and the compressive stress which came from the south. The uplift differentia in different area of the Tibetan Plateau should be more emphasized in the study on the uplift processes and dynamics of the whole Tibetan Plateau.