安徽铜陵冬瓜山铜矿床成矿流体特征及演化

Characteristics and evolution of ore-forming fluids associated with Yanshanian magmatic activity in Dongguashan copper deposit,Anhui Province,China

对安徽铜陵冬瓜山矿床内矽卡岩矿物、石英、方解石中的流体包裹体进行了岩相学和显微测温分析、群体包裹体气液相成分分析、单个包裹体气液相成分激光拉曼探针分析,探讨了成矿流体的特征及演化。研究表明,该矿床与燕山期岩浆热液有关的成矿流体,从早期矽卡岩阶段,经中期石英硫化物阶段,至晚期石英方解石阶段,是从高温、高盐度、富钾流体演化至中高温、中高盐度、富CO2(CH4)流体再至中低温、低盐度流体。成矿流体中的主要挥发分为H2O、CO2、CH4,并含少量C2H6、H2S、N2等,液相成分中的阳离子以Na+、K+为主,有少量Ca2+、Mg2+等,阴离子除Cl-外,SO42-的含量也较高。

Based on petrography, microthermometry and LRM analysis of fluid inclusions in garnet, diopside, quartz and calcite, this paper has discussed characteristics and evolution of ore-forming fluids in the Dongguashan copper deposit. The ore-forming fluids of Yanshanian magmatism evolved from high temperature, high salinity and K-rich fluids via moderate-high temperature and CO2 （CH4） rich fluids to moderate-low temperature and low salinity fluids. The analytical results suggest that the dominant volatiles in the ore-forming fluids are H2O, CO2 and CH4, with minor C2H6, H2S, N2 etc. Na^＋, K^＋ as well as Ca^2＋, Mg^2＋ are dominant cations whereas Cl^- and SO4^2- are major anions. High K and CO2 （CH4） constitute the main feature of the ore-forming fluids related to Yanshanian magmatism.