Study on the evolution of ore-formation fluids for Au-Sb ore deposits and the mechanism of Au-Sb paragenesis and differentiation in the southwestern part of Guizhou Province, China  

作　　者：WANG Zepeng XIA Yong SONG Xieyan LIU Jianzhong YANG Chengfu YAN Baowen 

机构地区：[1]State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences [2]Graduate University of Chinese Academy of Sciences [3]Geological Party 105, Guizhou Provincial Bureau of Geology and Mineral Exploration and Development [4]College of Resources and Environmental Engineering, Guizhou University

出　　处：《Chinese Journal Of Geochemistry》2013年第1期56-68,共13页中国地球化学学报

基　　金：financially supported jointly by the State Science and Technology Supporting Program(2006BAB01A13);the Self-research Project funded by the State Key Laboratory of Ore Deposit Geochemistry(Ore Deposit Special Research Project 2008.3-2);Guizhou Provincial Bureau of Geology and Mineral Resource Exploration and Development[Qian Di Kuang Ke(2009)No.11]

摘　　要：Ore deposits (occurrences) of Au, As, Sb, Hg, etc. distributed in Southwest Guizhou constitute the important portion of the low-temperature metallogenic domain covering a large area in Southwest China, with the Carlin-type Au and Sb deposits being the most typical ones. In this paper the Au and Sb ore deposits are taken as the objects of study. Through the petrographic analysis, microthermomitric measurement and Raman spectrophic analysis of fluid inclusions in gangue minerals and research on the S and C isotopic compositions in the gold ore deposits we can reveal the sources of ore-forming materials and ore-forming fluids and the rules of ore fluid evolution. Ore deposits of Au, Sb, etc. are regionally classified as the products of ore fluid evolution, and their ore-forming materials and ore fluids were probably derived mainly from the deep interior of the Earth. Fluid inclusion studies have shown that the temperatures of Au mineralization are within the range of 170-361℃,the salinities are 0.35 wt%-8 wt% NaCl eq.; the temperatures of Sb mineralization are 129.4-214℃ and the salinities are 0.18 wt%- 3.23 wt% NaCl eq.; the ore-forming fluid temperatures and salinities tend to decrease progressively. In the early stage (Au metallogenic stage) the ore-forming fluids contained large amounts of volatile components such as CO2, CH4, N2 and H2S, belonging to the H2O-CO2-NaCl fluid system; in the late stage (Sb metallogenic stage) the ore-forming fluids belong to the Sb-bearing H2O-NaCl system. The primitive ore-forming fluids may have experienced at least two processes of immiscibility: (1) when early ore-bearing hydrothermal solutions passed through rock strata of larger porosity or fault broken zones, CO2, CH4, N2 would escape from them, followed by the release of pressure, resulting in pressure release and boiling of primitive homogenous fluids, thereafter giving rise to their phase separation, thus leading to Au unloading and mineralization; and (2) in the late stage (Sb metallogenic stage ) a large volume of mOre deposits （occurrences） of Au, As, Sb, Hg, etc. distributed in Southwest Guizhou constitute the im- portant portion of the low-temperature metallogenic domain covering a large area in Southwest China, with the Carlin-type Au and Sb deposits being the most typical ones. In this paper the Au and Sb ore deposits are taken as the objects of study. Through the petrographic analysis, microthermomitric measurement and Raman spectrophic analysis of fluid inclusions in gangue minerals and research on the S and C isotopic compositions in the gold ore deposits we can reveal the sources of ore-forming materials and ore-forming fluids and the rules of ore fluid evolution. Ore deposits of Au, Sb, etc. are regionally classified as the products of ore fluid evolution, and their ore-forming materials and ore fluids were probably derived mainly from the deep interior of the Earth. Fluid inclusion studies have shown that the temperatures of Au mineralization are within the range of 170-361 ℃, the salinities are 0.35 wt%-8 wt% NaCl eq.; the temperatures of Sb mineralization are 129.4-214℃ and the salinities are 0.18 wt%- 3.23 wt% NaCl eq.; the ore-forming fluid temperatures and salinities tend to decrease progressively. In the early stage （Au metallogenic stage） the ore-forming fluids contained large amounts of volatile components such as CO2, CH4, N2 and H2S, belonging to the HEO-CO2-NaCl fluid system; in the late stage （Sb metallogenic stage） the ore-forming fluids belong to the Sb-bearing HEO-NaCl system. The primitive ore-forming fluids may have experienced at least two processes of immiscibility： （1） when early ore-bearing hydrothermal solutions passed through rock strata of larger porosity or fault broken zones, CO2, CH4, N2 would escape from them, followed by the release of pressure, resulting in pressure release and boiling of primitive homogenous fluids, thereafter giving rise to their phase separation, thus leading to Au unloading and mineralization; and （2） in the late stage （Sb metallogenic

关 键 词：成矿流体演化 中国西南地区 金锑矿床 分化 共生 贵州省 西南部 流体温度 

分 类 号：P618.51[天文地球—矿床学] Q254[天文地球—地质学]