四川天宝山大型铅锌矿床成矿流体及同位素地球化学  

Ore-forming fluid and isotope geochemistry of Tianbaoshan large carbonatehosted Pb-Zn deposit in Sichuan Province

作　　者：杨清 张均[1] 王健[1] 仲文斌 刘文浩[1] YANG Qing;ZHANG Jun;WANG Jian;ZHONG WenBin;LIU WenHao(Faculty of Earth Resources,China University of Geosciences,Wuhan 430074,Hubei,China;Guangxi Branch,China National Geological Exploration Center of Building Material Industry,Guilin 541001,Guangxi,China)

机构地区：[1]中国地质大学资源学院,湖北武汉430074 [2]中国建筑材料工业地质勘查中心广西总队,广西桂林541001

出　　处：《矿床地质》2018年第4期817-835,共19页Mineral Deposits

基　　金：地质调查项目(编号:12120114019701)资助成果

摘　　要：天宝山铅锌矿床位于扬子地块西南缘小江-甘洛断裂带和箐河-程海断裂带之间,是川滇黔多金属成矿带川西南地区重要的大型铅锌矿床。根据矿床流体包裹体岩相观察发现,天宝山铅锌矿床流体包裹体类型简单,主要为富液相包裹体,气相分数较小,少量纯液相包裹体。显微测温工作表明主成矿阶段流体温度峰值在110~140℃之间,w(NaCleq)集中于10%~14%,整体具有中低温、中低盐度特征,少部分流体包裹体w(NaCleq)为2%~6%,显示少量低盐度流体的混入。群体包裹体成分分析表明各期流体成分相似,液相为Na^+-Ca^(2+)-SO_4^(2-)-Cl^-型流体,气相主要为H_2O、CO_2,并有部分的H_2、CO及CH_4还原性气体。对以上流体包裹体成分数据分析发现成矿流体主要源于盆地热卤水,存在部分大气降水的参与。此外,C、O同位素、流体包裹体H、O同位素及硫化物S同位素组成表明,成矿流体除盆地卤水和大气降水来源外,还存在变质水及有机质流体来源,成矿还原硫主要来自灯影组硫酸盐和深源硫的混合。The Tianbaoshan Pb-Zn deposit, located between Xiaojiang-Ganluo fault and Qinghe-Chenghai fault at the southwest rim of Yangtze Block, is one of the most important Pb-Zn deposits in the Sichuan-Yunnan-Guizhou PbZn metallogenic province. According to the fluid inclusion petrography, the main fluid inclusions in the main oreforming stage of the Tianbaoshan Pb-Zn deposit are liquid-rich inclusions with low ratio of gas phase to fluid phase together with a small amount of pure liquid inclusions. The results of microscopic temperature measurement show that, at the main ore-forming stage, the fluid inclusions homogenization peak temperature is from 110℃ to 140℃, the salinity w（NaCleq） is concentrated between 10% and 14%, with middle-low temperature and middle-low characteristics;a small percentage of salinity w（NaCleq） is concentrated between 2% and 6%, indicating the incorporation of low salinity fluids. The composition analysis of fluid inclusiongroups shows that the fluid compositions are similar in each stage, the liquid part of ore-forming fluid belongs to Na＋-Ca2＋-SO42--Cl- system and the gas compositions of fluid inclusiongroups are mainly H2O, CO2, with a small amount of H2, CO and CH4 reducing gas. An analysis of the above data shows that the fluids were derived mainlyfrom basin brine, together with some meteoric water. In addition, carbon and oxygen isotopes, hydrogen and oxygen isotopic composition of fluid inclusions and sulfide sulfur isotope composition show that the ore-forming fluids were mainly sourced from brine and atmospheric precipitation in the basin, with the addition of metamorphic water and a small amount of organic matter, and that ore-forming reduced sulfur was mainly derived from Dengying Formation and the deep source.

关 键 词：地球化学 同位素地球化学 流体成分 铅锌矿 天宝山 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]