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青藏高原北缘的第四纪磨拉石沉积反映了高原所经历的隆升和剥蚀过程。本次工作对新疆西昆仑山前柯克亚剖面第四系磨拉石进行了砾石测量和统计。其结果为:砾石成分主要是沉积岩类,尤其在下部,以砂岩等碎屑岩为主;向上有较多的碳酸盐岩砾石,其中变质岩砾石较少,基本未见片麻岩砾石。这一结果表明当时的物源区主要是由中、新元古界、古生界和中生界的沉积岩系组成的,与现代地表在铁克里克及西昆仑出露的大套变质岩系明显不一致。由此可见,该地区在第四纪早期尚未具有现代地表的地质构造面貌特征,或者说尚未达到现今的隆起高度。现在铁克里克和西昆仑地区出露的大面积古老变质岩系是2.4Ma以后的构造隆升造成的。
Quaternary molasse deposits on the northern margin of the Tibetan Plateau reflect the uplift and erosion experienced by the plateau. This work carried out a gravel survey and statistics on Quaternary molasse in the Kekeya Section of the West Kunlun Mountains, Xinjiang. The results are as follows: The gravel components are mainly sedimentary rocks, especially in the lower part, dominated by clastic rocks such as sandstone; there are more carbonate gravels upward, of which metamorphic rocks have less gravel and no gneiss gravel. This result indicates that the source area was mainly composed of sedimentary rocks of Mesozoic, Neoproterozoic, Paleozoic and Mesozoic, and the large sets of metamorphic rocks exposed from modern surface in Tiecrick and Western Kunlun Department obviously inconsistent. It can be seen from this that the area did not have the features of the geological structure of the modern surface in the early Quaternary period, or that it has not reached the present uplift height. Now a large area of ancient metamorphic rocks exposed in the areas of Iron Creek and the West Kunlun Mountains was caused by tectonic uplift after 2.4 Ma.