Spatial-Temporal Framework of Shiquanhe-Laguoco-Yongzhu-Jiali Ophiolite Mélange Zone, Qinghai-Tibet Plateau and Its Tectonic Evolution

被引：0
|
作者：
Wang B. [1 ,2 ]
Liu H. [1 ,2 ]
Wang L. [1 ,2 ]
He J. [1 ,2 ]
Wang D. [1 ,2 ]
Li F. [1 ,2 ]
Wu Z. [1 ,2 ]
机构：
[1] Chengdu Center of China Geological Survey, Chengdu
[2] Research Center for Tibetan Plateau Geology, China Geological Survey, Chengdu
来源：
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2020年 / 45卷 / 08期
关键词：
Bangongco-Nujiang suture zone; Intra-oceanic subduction; Qinghai-Tibet Plateau; Shiquanhe-Laguoco-Yongzhu-Jiali ophiolite mélange zone; SSZ type ophiolite; Structural geology; Tectonic evolution; Tethyan;
D O I：
10.3799/dqkx.2020.083
中图分类号：
学科分类号：
摘要：
The Shiquanhe-Laguoco-Yongzhu-Jiali ophiolite mélange zone (SYMZ) is located between the Bangongco-Nujiang suture zone and the Yarlung-Zangbo suture zone in the central Qinghai-Tibet Plateau. The tectonic property of the SYMZ remains controversial, which restricts the application of archipelagic arc-basin system theory to the evolution of Qinghai-Tibet Plateau. Based on recent geological survey information, research results and comprehensive data analyses, in this paper, it summarizes the geological feature and discusses the tectonic process of the SYMZ. The SYMZ represents an independent ophiolitic mélange zone dividing the north Lhasa Terrane and central Lhasa Terrane, which is part of the Tethyan archipelagic arc-basin system. The typical ophiolite mélange suites are distributed in such places as Shiquanhe, Laguoco, Aso, Yongzhu and Kaimeng, and high precision geochronology data show that the main ocean basin was formed during 178-160 Ma, which was about 10 Ma later than the formation of the Bangongco-Nujiang ocean basin (188-162 Ma). The Aso ophiolitic mélange reflects that the SYMZ ocean basin had existed until 113 Ma. The Jurassic mafic rocks of the SYMZ show the geochemistry characteristics of MORB and IAT, belonging to the Oceanic Arc and MORB type ophiolites. The Early Cretaceous mafic rocks show both MORB and arc basalt characters, suggesting they probably formed in the tectonic setting of SSZ, different from the contemporaneous Bangongco-Nujiang ocean which was influenced by the mantle plume. The Jurassic boninites and bonibasalts series places like Laguoco, Yongzhu and Kaimeng were found in this study, indicating the intra-oceanic subduction of the SYMZ oceanic slab. Combined all these new discoveries with regional geological data, the spatial-temporal framework of the SYMZ Tethyan Ocean and its tectonic evolution history are established. The SYMZ Tethyan Ocean opened and spread in Late Triassic-Early Jurassic, the intra-oceanic subduction lasted during Middle-Late Jurassic, oceanic slab subduction begun in the Early Cretaceous, and finally ocean basin was extinct in the late Early Cretaceous. This study provides important geological evidences for understanding the lithosphere evolution and tectonic process of the Tethyan. © 2020, Editorial Department of Earth Science. All right reserved.
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页码：2764 / 2784
页数：20
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