安徽桂花冲铜矿床成矿流体演化特征研究  

Evolution of ore-forming fluids in Guihuachong copper deposit, Anhui Province

作　　者：左晓敏[1,2] 杜杨松[1] 曹毅[1] 岳紫龙[1] 张爱萍[1] 杜静国 黄文明[3] 宋晓媚 

机构地区：[1]中国地质大学地球科学与资源学院地质过程与矿产资源国家重点实验室,北京100083 [2]山东省地质博物馆,山东济南250000 [3]安徽省地质矿产勘查局321地质队,安徽铜陵244033

出　　处：《矿床地质》2016年第1期117-129,共13页Mineral Deposits

基　　金：中国地质调查局项目(编号:12120115034401;12120113069900);国家自然科学基金项目(编号:40672045)联合资助

摘　　要：桂花冲铜矿床是铜陵矿集区沙滩脚矿田内新发现的一个以斑岩型矿化为主的矽卡岩-斑岩复合型铜矿床。文章对该矿床的矿床地质和斑岩型矿化成矿流体进行了初步研究,旨在查明该矿床成矿流体的演化过程。根据脉体的穿切关系及矿物共生组合,桂花冲铜矿斑岩型矿化成矿过程可划分为钾化、硅化、石英黄铁矿、石英多金属硫化物和碳酸盐5个阶段。硅化阶段主要发育纯气体、含子矿物及富气相包裹体,石英黄铁矿阶段主要发育纯气体、富液相、富气相及含子矿物包裹体,石英多金属硫化物阶段及碳酸盐阶段主要发育富液相包裹体。从硅化阶段至碳酸盐阶段,成矿流体由高温（〉472.9℃）、高盐度（47.7%-74.0%）的岩浆热液逐渐向中低温（140.2-280.3℃）、低盐度（1.6%-7.7%）的岩浆热液和大气降水的混合流体演化,成矿过程中流体经历了沸腾及混合作用,混合作用是导致铜沉淀的主要机制。Located in the Shatanjiao orefield of the Tongling ore concentration area, the Guihuachong copper deposit is a newly-discovered skarn-porphyry composite deposit which is dominated by porphyry mineralization. In this study,the ore deposit geology and ore-forming fluids of porphyry mineralization were systematically studied in order to ascertain the fluids evolution. The ore-forming process can be divided into five stages according to the crosscutting relationships of the veinlets and the mineral assemblages as follows： Potassic alteration stage, silicification stage,quartz-pyrite stage, quartz-polymetallic sulfides stage and carbonation stage. The microscopic observation shows that fluid inclusions are mainly pure gaseous, daughter mineral-bearing, and gas-rich inclusions at the phyllic alteration stage, pure gaseous, daughter mineral-bearing, gas-rich and liquid-rich inclusions at the quartz-pyrite stage,and liquid-rich inclusions at the quartz-polymetallic sulfides and carbonate stages. From the silicification stage to the carbonation stage, ore-forming fluid changed from magmatic water characterized by high temperature（ 〉472. 9℃） and high salinity（ 47. 7% - 74. 0%） to the mixture of magmatic water and meteoric water characterized by medium-low temperature（ 140. 2 - 280. 3℃） and low salinity（ 1. 6% - 7. 7%）; in this process, ore-forming fluid experienced boiling and mixing, resulting in the precipitation of Cu.

关 键 词：地球化学 斑岩 流体包裹体 氢、氧同位素 桂花冲铜矿 安徽 

分 类 号：P618.41[天文地球—矿床学]