Zircon U-Pb Ages of Dongcuo Ophiolite in Western Bangonghu-Nujiang Suture Zone and Their Geological Significance

被引：17
|
作者：
Wu Y. [1 ,2 ]
Chen S. [2 ]
Qin M. [1 ]
Guo D. [1 ]
Guo G. [3 ]
Zhang C. [4 ]
Yang J. [2 ]
机构：
[1] CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology, Beijing Research Institute of Uranium Geology, Beijing
[2] Key Laboratory of Deep-Earth Dynamics of Ministry of Land and Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing
[3] Faculty of Earth Sciences, East China University of Technology, Nanchang
[4] Shanxi Museum of Geology, Taiyuan
来源：
| 2018年 / China University of Geosciences卷 / 43期
关键词：
Bangong-Nujiang suture zone; Gabbro; Geochronology; Ophiolite; Tectonic environment; Zircon U-Pb dating;
D O I：
10.3799/dqkx.2018.710
中图分类号：
学科分类号：
摘要：
The Dongcuo ophiolite is located at the western part of Bangong-Nujiang River suture zone, Gaize County. In spite of previous studies on its spacious distribution, tectonic environment and genesis, the key problem remains unresolved. Taking the gabbro of Dongcuo ophiolite as the research object, a detailed study of petrography, geochemistry, petrology and geochronology is carried out to understand the formation of Bangong-Nujiang ocean basin, the tectonic settings of the Dongcuo ophiolite. Compared with N-MORB, the major and trace elements of Dongcuo ophiolite are characterized by high content in Mg# and low content in K, Na, P, and Ti, the depletion of high field-strength elements (HFSE) of Hf, Zr, Nb and light rare earth element depletion. Geochemistry characteristics of the Dongcuo ophiolite indicate that it is originated from ~30% partial melting of depleted spinel lherzolite formed in the tectonic environment of subduction-related island arc or fore arc, belonging to super subduction zone (SSZ) ophiolite. The LA-ICP-MS of zircon U-Pb dating yields the age of 222±4.8 Ma (MSWD=0.5), providing the age constraint on the Dongcuo ophiolite (Late Triassic), and showing that it belongs to the Tethyan system of the Bangong-Nujiang River suture zone, which indicates the intra-oceanic subduction process. © 2018, Editorial Department of Earth Science. All right reserved.
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页码：1070 / 1084
页数：14
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