南秦岭柞水-山阳矿集区金盆梁金矿床成因——来自流体包裹体及C-H-O-S-Pb同位素的制约  

Genesis of Jinpenliang gold deposit in Zhashui-Shanyang ore cluster area,South Qinling:Constraints from fluid inclusions and C-H-O-S-Pb isotopes

作　　者：葛战林 顾雪祥[3,4] 章永梅 高永宝[1,2] 郝迪 郑艳荣 刘明 王辉 GE ZhanLin;GU XueXiang;ZHANG YongMei;GAO YongBao;HAO Di;ZHENG YanRong;LIU Ming;WANG Hui(Technology Innovation Center for Gold Ore Exploration,China Geological Survey,Xi’an 710100,Shaanxi,China;Xi’an Center of Mineral Resources Survey,China Geological Survey,Xi’an 710100,Shaanxi,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;The National 305 Project Office of Xinjiang,Urumqi 830000,Xinjiang,China)

机构地区：[1]中国地质调查局金矿勘查技术创新中心,陕西西安710100 [2]中国地质调查局西安矿产资源调查中心,陕西西安710100 [3]中国地质大学(北京),地球科学与资源学院,北京100083 [4]新疆维吾尔自治区人民政府国家305项目办公室,新疆乌鲁木齐830000

出　　处：《矿床地质》2024年第4期877-898,共22页Mineral Deposits

基　　金：陕西省自然科学基础研究计划资助项目(编号:2023-JC-QN-0284,2024JC-YBQN-0349);国家自然科学基金重点项目(编号:42130804);中国地质调查局项目(编号:DD20220966、DD20230060、DD20230378);新疆维吾尔自治区重点研发计划项目(编号:2023B03016);新疆维吾尔自治区“天池英才”引进计划项目联合资助。

摘　　要：金盆梁是南秦岭柞水-山阳矿集区勘查的一处微细浸染型金矿床,矿床成因与成矿机制尚不清楚。矿体产于上泥盆统桐峪寺组粉砂质板岩和钙质板岩中,以浸染状、脉状金锑矿化为主,成矿过程可划分为3个阶段:毒砂-黄铁矿-硅化阶段(Ⅰ)、石英-辉锑矿-白铁矿±锑氧化物阶段(Ⅱ)和方解石-石英阶段(Ⅲ)。流体包裹体及C-H-O-S-Pb同位素研究结果显示,Ⅱ阶段主要为金锑矿化,以H_(2)O-NaCl两相包裹体占绝对优势,成矿流体属于中温(200~290℃)、低盐度(w(NaCl_(eq))为0~6.0%)、低密度(0.64~0.99 g/cm^(3))的H_(2)O-NaCl±CO_(2)体系,以循环大气降水为主。无矿化的Ⅲ阶段主要发育H_(2)O-NaCl两相包裹体,含少量CO_(2)-H_(2)O-NaCl±CH_(4)、纯CO_(2)±CH_(4)及含子晶多相包裹体,流体以中低温(140~280℃)、低盐度(w(NaCl_(eq))为2.0%~8.0%)、低密度(0.68~1.02 g/cm^(3))的富CO_(2)-H_(2)O-NaCl±CH_(4)体系为主,或存在少量高温、高盐度、高密度H_(2)O-NaCl体系的岩浆热液混入。硫化物δ^(34)S值为较大负值(−12.50‰~−10.20‰),Pb同位素组成具上地壳源铅特征,成矿物质主要来源于围岩地层。综合研究表明,金盆梁金矿的成因类型属于卡林型金矿,水-岩反应(围岩硫化作用)是金富集沉淀的主要机制。The Jinpenliang is an explored micro-disseminated gold deposit in the Zhashui-Shanyang ore cluster area,South Qinling.To date,its ore genesis and metallogenic mechanism are still unclear.These Au-Sb orebodies at Jinpenliang deposit are hosted by the silty slate and calcareous slate of the Upper Devonian Tongyusi Formation,occurring as disseminated and veinlet mineralization.The ore-forming process can be classified into three stages,namely,arsenopyrite-pyrite-silicification stage(Ⅰ),quartz-stibnite-marcasite±antimony oxide stage(Ⅱ),and calcite-quartz stage(Ⅲ).Fluid inclusion and C-H-O-S-Pb isotope studies indicate that inclusions in stageⅡquartz(Au and Sb mineralization)are dominated by the H_(2)O-NaCl two-phase inclusions.The metallogenic fluid is characterized by a medium-temperature(200~290℃),low-salinity(w(NaCl_(eq))=0~6.0%),and low-density(0.64~0.99 g/cm^(3))H_(2)O-NaCl±CO_(2)system,predominately originated from meteoric water.Besides the H_(2)O-NaCl twophase inclusions,there are a small amount of CO_(2)-H_(2)O-NaCl±CH_(4)inclusions,pure CO_(2)±CH_(4)inclusions,and daughter mineral-bearing multiphase inclusions identified in quartz of stageⅢbarren veins.This nonmetallogenic fluid primarily belongs to a medium to low-temperature(140~280℃),low-salinity(w(NaCl_(eq))2.0%~8.0%),and low-density(0.68~1.02 g/cm^(3))CO_(2)-H_(2)O-NaCl±CH_(4)system,with a high-temperature,high-salinity,and high-density H_(2)O-NaCl system of magmatic water mixed in.Theδ^(34)S values of sulfides range from−12.50‰to−10.20‰,and the Pb isotopic compositions have the characteristics of the upper crust,implying that the ore-froming materials were mainly derived from wall rocks.Comprehensive studies show that the Jinpenliang deposit can be classed as a typical Carlin-type gold deposit,and the water-rock reaction(sulfidation)is the crucial mechanism for gold precipitation.

关 键 词：矿床成因 流体包裹体 C-H-O-S-Pb同位素 金盆梁金矿床 南秦岭 

分 类 号：P618.51[天文地球—矿床学]