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CO2三相(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％NaCleqv,指示成矿流体主要为中-低温、中-低盐度和低密度的H2O-CO2-NaCl体系流体.S3阶段石英流体包裹体的δDv-SMOW值为-89.3‰～-75.9‰,818OH2O值为4.77‰～8.01‰;S2和S3阶段黄铁矿原位硫同位素数据δ34S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.
Abstract
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),CO2-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 ℃,and salinities of 2.8％～17.6％,2.9％～11.9％,1.9％～14.2％and 1.2％～9.1％NaCleqv,respectively,indicating that the ore-forming fluid is mainly the medium-low temperature,medium-low salinity and low density H2O-CO2-NaCl system fluid.δDV-SMOW and δ18OH2O values of inclusion fluids in quartz of Stage S3 vary from-89.30‰ to-75.9‰ and 4.77‰ to 8.0 1‰,respectively.In situ sulfur isotopic data of pyrites of Stage S2 and Stage S3 show that their δ34S values vary from-3.‰ 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.
基金项目
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)
湖北省自然资源厅地质勘查基金管理中心项目([2022]7号)
湖北省地质局科技处项目(KJ2022-10)
湖北省地质局科技处项目(KJ2022-47)
湖北省地质局地勘处项目(KCDZ2023-07)
维普
万方数据