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DIVISION AND CHARACTERISTICS OF THE GEOTECTONIC UNITS OF YUNLING EPICONTINENTAL ARC IN NORTHWEST YUNNAN |
WANG Xue-wu1, LIU Feng-xiang1, LI Xin-ren1, YAN Cheng-min2, ZHOU Xi-lin1, WANG Chang-bing1 |
1. No. 209 Geological Party, Yunnan Bureau of Geology for Nuclear Industry, Kunming 650031, China; 2. Regional Geological Survey Party, Yunnan Bureau of Geology and Mineral Resources, Kunming 653100, China |
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Abstract With field survey and data processing, the structural characteristics of the Yunling epicontinental arc in Northwest Yunnan are clarified. This region is divided into 6 four-grade tectonic units, i.e. Xuelongshan Rock Group (Pt1Xl), Deqing Blocks (Pz1), Pantiange acidic volcanic magmatic arc (T2), Gongnong inter-arc basin (T2), Cuiyibi intermediate-basic volcanic magmatic arc(T1-2), and Ludian volcanic arc-syn-collisional granite(T). The former two units belong to the basements of island arcs; while latter four, the main bodies. The rock associations and deformation-metamorphism of each unit are various obviously. The main bodies of island arcs were formed from Early Triassic to early Late Triassic, as a product of the westward subduction and collisional orogeny of Jinshajiang ocean basin. The main bodies of island arcs are covered by Upper Triassic strata in angular unconformity.
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Received: 18 July 2016
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