Zircon U–Pb and Hf isotopic constraints on the onset time of India-Asia collision
Zircon U–Pb and Hf isotopic constraints on the onset time of India-Asia collision
复制标题
DOI：
10.2475/02.2014.04
复制
发表时间：
2014-02
影响因子：
2.9
通讯作者：
Fu-Yuan Wu;Weiqiang Ji;Jian‐Gang Wang;Chuan-Zhou Liu;Sun‐Lin Chung;P. Clift
中科院分区：
文献类型：
--
作者：
Fu-Yuan Wu;Weiqiang Ji;Jian‐Gang Wang;Chuan-Zhou Liu;Sun‐Lin Chung;P. Clift
印度与亚洲的初始碰撞时间一直存在极大的争议，尽管事实上，这是至关重要的制约造山作用和随后的喜马拉雅山脉和青藏高原的演化。本文报道了西藏南部两个主要前陆盆地，即桑丹林盆地和江孜盆地的碎屑锆石U-Pb和Hf同位素分析结果。我们的数据表明，亚洲衍生的碎屑沉积物开始对印度大陆边缘的沉积早于一般认为的，在1060 Ma在雅鲁藏布江缝合带附近的两个盆地。在西藏南部，没有证据表明在新特提斯洋内存在洋内弧。我们的结论是，1060 Ma可以用来限制印度-亚洲碰撞的开始时间，至少在西藏中部。在这一初始碰撞之后，新特提斯的闭合向西和向东传播，最终闭合分别发生在喜马拉雅山脉西北部和东部的2.50和2.45 Ma。我们的结论与以往认为印度-亚洲碰撞可能始于喜马拉雅西北部并以穿时方式向东传播的观点有很大不同。
The time of initial collision between India and Asia has been extremely controversial despite the fact that it is vital to constraining the orogenesis and subsequent evolution of the Himalayas and Tibetan Plateau. Here we report U–Pb and Hf isotope analysis of detrital zircons from two principal foreland basins, that is, the Sangdanlin and Gyangze basins respectively in the western and central parts of southern Tibet. Our data suggest that Asian-derived clastic sediments started contributing to sedimentation on the Indian continental margin earlier than generally thought, at ∼60 Ma in both basins near the Yarlung-Zangbo Suture Zone. In southern Tibet, no evidence for the existence of an intra-oceanic arc within the Neotethys is observed. We conclude that ∼60 Ma can be used to constrain the onset time of the India-Asia collision, at least in central Tibet. After this initial collision, closure of the Neotethys propagated both westward and eastward, with the final closure occurring at ∼50 and ∼45 Ma in northwestern and eastern Himalayas, respectively. Our conclusion differs significantly from the previous view that the India-Asia collision may have started in northwestern Himalaya and propagated eastward with diachronous suturing.