Constraints on mountain building in the northeastern Tibet: Detrital zircon records from synorogenic deposits in the Yumen Basin.
Constraints on mountain building in the northeastern Tibet: Detrital zircon records from synorogenic deposits in the Yumen Basin.
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DOI：
10.1038/srep27604
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发表时间：
2016-06-09
影响因子：
4.6
通讯作者：
Pang J
中科院分区：
文献类型：
--
作者：
Wang W;Zhang P;Yu J;Wang Y;Zheng D;Zheng W;Zhang H;Pang J
新生代盆地和山脉构成了印度-欧亚大陆碰撞形成的西藏东北部高地。盆地中的沉积岩提供了对山脉折返历史和导致青藏高原向东北生长的构造过程的直接洞察。本文对北祁连山、北山现代河流砂和玉门盆地砂岩的碎屑锆石U-Pb年龄进行了分析和对比。锆石年龄分布表明，盆地内24.2- 16.7Ma的地层均来自北山，16 Ma左右盆地物源迅速转换为北祁连山。这些结果表明，早期的变形沿着北山在~24 Ma被北祁连山的增长在~16 Ma所取代。我们的结论是，远场效应与印支-亚洲碰撞可能是由于渐新世变形在北山，但北祁连山的出现在16 Ma可能反映了最近的青藏高原的向外生长，可能是由一些岩石圈地幔在西藏中部的去除。
The Cenozoic basins and ranges form the high topography of the northeastern Tibet that resulted from the India-Eurasia collision. Sedimentary rocks in the basins provide direct insight into the exhumation history of the ranges and the tectonic processes that led to the northeastward growth of the Tibetan Plateau. In this study, we analyzed and compared detrital zircon U-Pb ages from sands of modern rivers draining the Bei Shan, and North Qilian Shan and sandstones from the Yumen Basin. The zircon age distributions indicate that the strata dated to 24.2-16.7 Ma in the basin were derived from the Bei Shan, and the basin provenance changed rapidly to the North Qilian Shan terrane at ~16 Ma. These results suggest that an early stage of deformation along the Bei Shan at ~24 Ma was replaced by the growth of the North Qilian Shan at ~16 Ma. We conclude that the far-field effect associated with the Indo-Asian collision may result from Oligocene deformation in the Bei Shan, but the emergence of the North Qilian Shan at ~16 Ma could reflect the most recent outward growth of the Tibetan Plateau that may have been caused by the removal of some lithospheric mantle beneath central Tibet.