豫西南高庄金矿床流体包裹体组合研究及其成矿流体特征  

Research on fluid inclusion assemblages and ore-forming fluid of Gaozhuang gold deposit in Southwestern Henan

作　　者：向世红 薛春纪[2] 彭姣 张智慧 曹纪虎 杨永千 XIANG ShiHong;XUE ChunJi;PENG Jiao;ZHANG ZhiHui;CAO JiHu;YANG YongQian(Henan Non-ferrous Metals Geological Exploration Institute, Zhengzhou 450016, Henan, China;School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China;Henan Province Non-ferrous Metals Geological and Mineral Resource Bureau, Zhengzhou 450016, Henan, China)

机构地区：[1]河南省有色金属地质勘查总院,河南郑州450016 [2]中国地质大学地球科学与资源学院,北京100083 [3]河南省有色金属地质矿产局,河南郑州450016

出　　处：《矿床地质》2017年第5期1197-1212,共16页Mineral Deposits

基　　金："北秦岭造山带(河南段)银金多金属矿成矿规律及找矿方法研究"项目(编号:YSDK2014-01);"豫南大别山北麓地区钼多金属成矿规律及找矿方法研究"项目(编号:12120113091200);"河南省西峡县水地沟地区金多金属矿成矿规律与成矿预测"项目(编号:YSDK2012-01)联合资助

摘　　要：高庄金矿床形成于华北板块和扬子板块造山后的板内伸展环境,矿体是二郎坪群中充填于平行造山带走向的脆韧性剪切带中的石英-金多金属硫化物矿脉。本次运用"流体包裹体组合"(FIA)方法进行流体包裹体特征研究。研究表明,高庄金矿含矿石英中包裹体主要有CO_2-H_2O型三相包裹体、CO_2包裹体和水溶液包裹体3种类型,其中,CO_2-H_2O型三相包裹体为主体类型,完全均一温度变化范围为286~349℃,w(Na Cleq)为0.41%~4.14%,估算流体密度为0.788~0.874 g/cm3,成矿压力为130~160 MPa,成矿深度为4.8~5.9 km,成矿流体具有中温,富CO_2、低盐度的特征。在同一视域内可见CO2-H2O型三相包裹体和水溶液包裹体共存,均一方式各异,且均有相近的均一温度,指示存在流体不混溶作用。成矿流体中水的δDH_2O=-83.4‰^-76.3‰,δ18OH_2O=5.8‰~7.1‰,显示成矿流体来自于岩浆热液。结合区域构造背景,认为高庄金矿床为形成于华北板块与扬子板块碰撞造山作用后,板块内部构造变形过程中形成的中温岩浆热液型金矿。The Gaozhuang gold deposit was formed in the extension environment after the collision between North China and Yangtze plates. Orebodies occur as quartz-polymetallic sulfide veins in the Erlangping Group, filling in the brittle-ductile shear zone which is parallel to the orogenic belt. Fluid inclusions assemblage（ FIA） uniform temperature method was used to investigate the fluid inclusion characteristics. The results show that the samples contain three different types of fluid inclusions, i. e., CO2-H2O three phases inclusions, CO2 inclusions and aqueous inclusions, in which the CO2-H2O three phases inclusions are dominant. The total homogenization temperature varies from 284℃ to 349℃ and w（ Na Cleq） values vary from 0. 41% to 4. 14%. According to the analysis of the CO2-H2O three phases inclusions, the authors infer that the ore-forming fluid densities range from 0. 788 g/cm3 to 0. 874 g/cm3; thus the trapping pressure should be 130 ~ 160 MPa, corresponding to ore-forming depth of 4. 8 ~ 5. 9 km.Characteristics of the ore-forming fluid are high temperature, rich CO2 and low salinity. CO2-H2O three phases inclusions and aqueous inclusions with similar total homogenization temperatures could be found in the same horizon,which implies the presence of fluids immiscibility. Hydrogen and oxygen isotopes show that δDH2O=-83. 4‰ ^-76. 3‰,δ18 OH2O= 5. 8‰ ~ 7. 1‰, suggesting that ore-forming fluid was mainly from magmatic water. Combined with regional tectonic background, the authors hold that the Gaozhuang gold deposit is a medium temperature magmatic hydrothermal gold deposit.

关 键 词：地球化学 流体包裹体 均一温度 盐度 氢-氧同位素 高庄金矿 豫西南 

分 类 号：P618.51[天文地球—矿床学]