甘肃塘坝金矿床成矿流体特征及矿床成因  

Ore-forming fluids characteristics and deposit genesis of Tangba Gold Deposit in Gansu

作　　者：马塬皓 刘云华[1] 赵强 吴勇 李小严 邓楠 Ma Yuanhao;Liu Yunhua;Zhao Qiang;Wu Yong;Li Xiaoyan;Deng Nan(School of Earth Science and Resources,Chang'an University;Third Institute Geological and Mineral Exploration,Gansu Provincial Bureau of Geology and Mineral Resources)

机构地区：[1]长安大学地球科学与资源学院,710054 [2]甘肃省地质矿产勘查开发局第三地质矿产勘查院

出　　处：《黄金》2020年第2期3-11,共9页Gold

基　　金：国家自然科学青年基金面上项目(41872219);中国地质调查局整装勘查综合研究项目(121201004000172201-48)

摘　　要：塘坝金矿床位于西秦岭金成矿带南部文县—康县金成矿亚带东段,为石英脉型金矿床。野外地质调查发现,矿体主要产于花岗斑岩脉附近的断裂中,在空间上与花岗斑岩脉关系密切,成矿作用可划分为3个阶段。流体包裹体显微测温结果表明:不同阶段成矿流体包裹体类型相近,矿床成矿温度为156.9℃~303.2℃,盐度为1.82%~15.67%,密度为0.76~0.99 g/cm 3,深度为5.18~7.43 km;成矿流体具有中低温度、中低盐度、低密度、中浅成相特征。包裹体激光拉曼光谱分析显示,包裹体气相成分主要为CO 2、H 2O,含少量N 2,液相成分主要为H 2O,属于H 2O-NaCl±CO 2体系。氢-氧-硫同位素分析结果表明,塘坝金矿床δ18 O H 2O为5.98‰~9.87‰,δD V-SMOW为-80.6‰^-74.5‰,δ34 S为-1.9‰~8.0‰;结合矿床野外产出特征,成矿流体主要来源于岩浆热液。综合分析认为,该矿床为与岩浆作用有关的中低温度、中低盐度岩浆期后热液型金矿床。Tangba Gold Deposit is located in the east part of Wenxian-Kangxian gold metallogenic sub-belt in the south part of west Qinling gold metallogenic belt and is a quartz vein type gold deposit.Outdoor geological survey finds that the ore body mainly occurs in the fault around the granite-porphyry dyke and is closely related to granite porphyry spatially.The metallogenesis can be classified into 3 phases.Fluid inclusion microscopic thermometry results show that fluid inclusion types in different phases are similar,the metallogenic temperature of the deposit is 156.9℃-303.2℃,salinity is 1.82%-15.67%,density is 0.76-0.99 g/cm 3,depth is 5.18-7.43 km;the ore-forming fluids are characterized by medium low temperature,medium low salinity,low density and medium hypabyssal features.Inclusion laser Raman spectrum analysis shows that the gas phase compositions in inclusions are mainly CO 2,H 2O and minor N 2,the liquid phase compositions are mainly H 2O,indicating the inclusion belong to a H 2O-NaCl±CO 2 system.H-O-S isotopic analysis results show that theδ18 O H 2O in Tangba Gold Deposit is 5.98‰-9.87‰,δD V-SMOW is-80.6‰--74.5‰,δ34 S is-1.9‰~8.0‰;based on the outdoor occurrence characteristics of the deposit,the ore-forming fluids mainly originate from magmatic fluids.Comprehensive analysis takes that the deposit is a me-dium low temperature,medium low salinity post-magmatic hydrothermal gold deposit related to magmatism.

关 键 词：流体包裹体 成矿流体 同位素 矿床成因 塘坝金矿床 

分 类 号：TD11[矿业工程—矿山地质测量] P618.51[天文地球—矿床学]