Genesis of the Gold Deposit in the Indus-Yarlung Tsangpo Suture Zone,Southern Tibet:Evidence from Geological and Geochemical Data

作     者：ZHANG Xiong DENG Xueguo YANG Zhusen HOU Zengqian ZHENG Yuanchuan LIU Yingchao ZHAO Xiaoyan XU Bo PEI Yingru ZHOU Jinsheng ZHAO Miao YUAN Jianfei 

作者机构：School of Earth sciences and ResourcesChina University of GeosciencesBeijing MLR Key Laboratory of Metallogeny and Mineral AssessmentInstitute of Mineral ResourcesChinese Academy of Geological Sciences Institute of Metallurgical Geology and ExplorationSichuan Institute of GeologyChinese Academy of Geological Sciences ARC Centre of Excellence for Core to Crust Fluid System(CCFS) and GEMOCDepartment Of Earth and Planetary SciencesMacquarie University 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2017年第91卷第3期

页      面：947-970页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：provided by the National Key Research and Development Program of China "Deep Structure and Ore-forming Process of Main Mineralization System in Tibetan Orogen"(2016YFC0600300) the National Basic Research Program of China (2011CB403104) the China Geological Survey (12120113037901) the National Natural Science Foundation of China(41320104004) and(41503040) 

主　　题：geology gold mineralization Nianzha Deposit Indus-Yarlung Tsangpo suture zone Tibet 

摘      要：The Nianzha gold deposit, located in the central section of the Indus-Yarlung Tsangpo suture （IYS） zone in southern Tibet, is a large gold deposit （Au reserves of 25 tons with average grade of 3.08 g/t） controlled by a E-W striking fault that developed during the main stage of Indo-Asian collision （-65-41 Ma）. The main orebody is 1760 m long and 5.15 m thick, and occurs in a fracture zone bordered by Cretaceous diorite in the hanging wall to the north and the Renbu tectonic melange in the footwall to the south. High-grade mineralization occurs in a fracture zone between diorite and ultramafic rock in the Renbu tectonic melange. The wall-rock alteration is characterized by silicification in the fracture zone, serpentinization and the formation of talc and magnesite in the uitramafic unit, and chloritization and the formation of epidote and calcite in diorite. Quartz veins associated with Au mineralization can be divided into three stages. Fluid inclusion data indicate that the deposit formed from H20-NaCl-organic gas fluids that homogenize at temperatures of 203℃-347℃ and have salinities of 0.35wt%-17.17wt% NaCI equivalent. The quartz veins yield δ18Ofluid values of 0.15‰-10.45‰, low δDv-SMow values （-173%o to -96%o）, and the δ13C values of-17.6‰ to -4.7‰, indicating the ore-forming fluids were a mix of metamorphic and sedimentary orogenic fluids with the addition of some meteoric and mantle-derived fluids. The pyrite within the diorite has δ34SV-CDT values of -2.9‰-1.9‰（average -1.1‰）, 206pb/204pb values of 18.47- 18.64, 207pb/204pb values of 15.64-15.74, and 208pb/204pb values of 38.71-39.27, all of which are indicative of the derivation of S and other ore-forming elements from deep in the mantle. The presence of the Nianzha, Bangbu, and Mayum gold deposits within the IYS zone indicates that this area is highly prospective for large orogenic gold deposits. We identified three types of mineralization within the IYS, namely Bangbu-type accretionary, Mayum-type micro