| Geochronology, Geochemistry and Tectonic Setting of the Bairiqiete Granodiorite Intrusion (Rock Mass) from the Buqingshan Tectonic Mélange Belt in the Southern Margin of East Kunlun |
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| 作者姓名： | LI Zuochen PEI Xianzhi LI Ruibao PEI Lei LIU Chengjun CHEN Youxin LIU Zhanqing CHEN Guochao XU Tong YANG Jie and WEI Bo |
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| 作者单位： | 1 Key Laboratory of Western China’s Mineral Resources and Geological Engineering, Ministry of Education, Faculty of Earth Science and Resources, Chang’an University, Xi’an 710054, Shaanxi, China
2 Faculty of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China
3 College of Earth Sciences, Guilin University of Technology, Guilin 541004, China |
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| 基金项目： | This study was supported financially by the National Nature Sciences Foundation of China (No. 41172186), the Fundamental Research Funds for the Central Universities (No. CHD2011TD020), and the Commonweal Geological Survey, The Aluminum Corporation of China and the Land-Resources Department of Qinghai Province (No. 200801). |
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| 摘 要： | This study focuses on the zircon U–Pb geochronology and geochemistry of the Bairiqiete granodiorite intrusion(rock mass) from the Buqingshan tectonic mélange belt in the southern margin of East Kunlun. The results show that the zircons are characterized by internal oscillatory zoning and high Th/U(0.14–0.80), indicative of an igneous origin. LA–ICP–MS U–Pb dating of zircons from the Bairiqiete granodiorite yielded an age of 439.0 ± 1.9 Ma(MSWD = 0.34), implying that the Bairiqiete granodiorite formed in the early Silurian. Geochemical analyses show that the rocks are medium-K calc-alkaline, relatively high in Al2O3(14.57–18.34 wt%) and metaluminous to weakly peraluminous. Rare-earth elements have low concentrations(45.49–168.31 ppm) and incline rightward with weak negative to weak positive Eu anomalies(δEu = 0.64–1.34). Trace-element geochemistry is characterized by negative anomalies of Nb, Ta, Zr, Hf and Ti and positive anomalies of Rb, Th and Ba. Moreover, the rocks have similar geochemical features with adakites. The Bairiqiete granodiorite appears to have a continental crust source and formed in a subduction-related island-arc setting. The Bairiqiete granodiorite was formed due to partial melting of the lower crust and suggests subduction in the Buqingshan area of the Proto-Tethys Ocean.
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| 关 键 词： | granodiorite zircon LA–ICP–MS U–Pb age Early Paleozoic Buqingshan tectonic mélange belt Proto-Tethys |
| 收稿时间： | 2013/11/2 0:00:00 |
| 修稿时间： | 2014/1/20 0:00:00 |
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