Geochemistry of Pyrite from the Gangcha Gold Deposit, West Qinling Orogen, China: Implications for Ore Genesis  

作　　者：NIE Xiao SHEN Junfeng LIU Haiming DU Baisong WANG Shuhao LI Jie XU Liwei WANG Ran 

机构地区：[1]School of Earth Sciences and Resources,China University of Geosciences [2]Département de géologie et de génie géologique,Université Laval [3]Inner Mongolia Ninth Geology Mineral Exploration and Development Co.,Ltd [4]Jinyou Geological Exploring Co.,Ltd [5]The Gold of CAPF

出　　处：《Acta Geologica Sinica(English Edition)》2017年第6期2164-2179,共16页地质学报（英文版）

基　　金：The National Natural Science Foundation of China (41072070) provided financial support for this study

摘　　要：The Gangcha gold deposit was discovered in 2011 in the Xiahe-Hezuo region, West Qinling Orogen, China. Five types of pyrite have been identified in the ore according to the detailed mineral paragenetic studies. Geochemical data are presented for type I pyrite （pyl） rim-core zonation and for the different types of pyrite based on in-situ laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS） and electron probe microanalysis （EPMA）. The results show that pyrites are characterized with heterogeneous Au concentrations, which indicate that Au occurs mainly as micro- or nano-particle native inclusions. Time-resolved depth profiles demonstrate that As, Co and Ni occur as solid solutions in pyrite, whereas Cu, Pb, Zn and Ag occur mainly as inclusions. Trace element concentrations differ between rims and cores in pyl, and the differences also exist within different pyrite types. These differences indicate complex chemical evolution of the ore-forming fluids, and the overall geology, geochronology, and stable isotope and pyrite data suggest that the ore-forming fluids were closely linked to magmatic activity during the Triassic Period in West Qinling orogenic belt.The Gangcha gold deposit was discovered in 2011 in the Xiahe-Hezuo region, West Qinling Orogen, China. Five types of pyrite have been identified in the ore according to the detailed mineral paragenetic studies. Geochemical data are presented for type I pyrite （pyl） rim-core zonation and for the different types of pyrite based on in-situ laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS） and electron probe microanalysis （EPMA）. The results show that pyrites are characterized with heterogeneous Au concentrations, which indicate that Au occurs mainly as micro- or nano-particle native inclusions. Time-resolved depth profiles demonstrate that As, Co and Ni occur as solid solutions in pyrite, whereas Cu, Pb, Zn and Ag occur mainly as inclusions. Trace element concentrations differ between rims and cores in pyl, and the differences also exist within different pyrite types. These differences indicate complex chemical evolution of the ore-forming fluids, and the overall geology, geochronology, and stable isotope and pyrite data suggest that the ore-forming fluids were closely linked to magmatic activity during the Triassic Period in West Qinling orogenic belt.

关 键 词：PYRITE GEOCHEMISTRY Gangcha gold deposit West Qinling Qrogen 

分 类 号：P618.51[天文地球—矿床学]