大别造山带双庙关金矿床成矿流体特征与成因  

Ore fluid characteristics and genesis of the Shuangmiaoguan gold deposit,Dabie

作　　者：汪兴韦 刘嘉 李红梅 朱金 欧阳佳岑 刘晓阳 于永顺 杜文洋 付乐兵[1] WANG Xing-wei;LIU Jia;LI Hong-mei;ZHU Jin;OUYANG Jia-cen;LIU Xiao-yang;YU Yong-shun;DU Wen-yang;FU Le-bin(School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;Hubei Geological Survey,Wuhan 430034,China;Hubei Research Center of Geological Exploration and Engineering Technology,Wuhan 430034,China)

机构地区：[1]中国地质大学(武汉)资源学院,武汉430074 [2]湖北省地质调查院,武汉430034 [3]湖北省地质勘查工程技术研究中心,武汉430034

出　　处：《矿物岩石地球化学通报》2024年第3期579-592,共14页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：中国地质调查局项目(DD20221695);湖北省自然资源厅地质勘查基金管理中心项目(2019-16,[2022]7号);湖北省地质局科技处项目(KJ2022-10,KJ2022-47);湖北省地质局地勘处项目(KCDZ2023-07)。

摘　　要：湖北省麻城市双庙关金矿床是大别造山带中部新发现的金多金属矿床。本文在详细的野外地质调查和岩矿相学研究基础上,将成矿过程分为S1、S2、S3和S4四个阶段,其矿物组合分别为石英+钾长石±黄铁矿、石英+黄铁矿±黄铜矿、石英+黄铁矿+黄铜矿±金银碲化物和石英+碳酸盐,其中S3为主成矿阶段。四个成矿阶段的石英中发育富液两相(WL型)、富气两相(WV型)、含CO_(2)三相(C型)和含子矿物多相(S型)包裹体,其均一温度分别为226~445、234~422、258~392和152~215℃,盐度分别为2.8%~17.6%、2.9%~11.9%、1.9%~14.2%和1.2%~9.1%NaCl_(eqv),指示成矿流体主要为中-低温、中-低盐度和低密度的H_(2)O-CO_(2)-NaCl体系流体。S3阶段石英流体包裹体的δD_(V-SMOW)值为-89.3‰~-75.9‰,δ^(18)O_(H_(2)O)值为4.77‰~8.01‰;S2和S3阶段黄铁矿原位硫同位素数据δ^(34)S值为-3.6‰~1.6‰,指示成矿流体具有深源岩浆流体特征。综合分析认为,双庙关金矿床的成矿流体可能来源于岩浆热液,成矿过程中流体的不混溶作用是金沉淀的重要因素。The Shuangmiaoguan gold deposit in the Macheng City,Hubei Province,is a newly discovered Au polymetallic deposit located in the central part of the Dabie orogenic belt.However,its origin is still unclear.Through the detailed field geological survey and indoor petrological and mineralogical studies,in this paper,4 stages of the mineralization process have been identified,with respective mineral assemblages of quartz+K-feldspar±pyrite(S1),quartz+pyrite±chalcopyrite(S2),quartz+pyrite+chalcopyrite±gold and silver telluride(S3),and quartz+carbonate(S4).Especially,Stage S3 is the main mineralization stage of the deposit.Four types of fluid inclusions developed in quartz.They include fluid-rich two-phase fluid inclusions(Type WL),gas-rich two-phase fluid inclusions(Type WV),CO_(2)-bearing three-phase fluid inclusions(Type C)and daughter-mineral-bearing multiphase fluid inclusions(Type S).They have homogeneous temperatures of 226~445,234~422,258~392 and 152~215°C,and salinities of 2.8%~17.6%,2.9%~11.9%,1.9%~14.2% and 1.2%~9.1%NaCl_(eqv),respectively,indicating that the ore-forming fluid is mainly the medium-low temperature,medium-low salinity and low density H_(2)O-CO_(2)-NaCl system fluid.δD_(V-SMOW) and δ^(18)OH_(2)O values of inclusion fluids in quartz of Stage S3 vary from−89.3‰to−75.9‰ and 4.77‰ to 8.01‰,respectively.In situ sulfur isotopic data of pyrites of Stage S2 and Stage S3 show that their δ^(34)S values vary from−3.6‰ to 1.6‰,indicating that the ore-forming fluid has characteristics of deeply sourced magmatic fluid.Comprehensive analysis suggests that the ore-forming fluid of the Shuangmiaoguan gold deposit is mainly derived from magmatic hydrothermal fluids.The fluid immiscibility is an important factor caused the gold precipitation in the ore-forming process.

关 键 词：矿床成因 流体包裹体 岩浆热液 脉型金矿床 双庙关金矿床 

分 类 号：P611[天文地球—矿床学] P611.11[天文地球—地质学] P618.51