江南钨矿带香炉山钨矿床稳定同位素地球化学示踪  

Stable isotopic geochemistry of the Xianglushan tungsten deposit in the Jiangnan tungsten metallogenic belt

作　　者：高任 张明华 汪国华 温润涛 陈天迪 GAO Ren;ZHANG Ming-hua;WANG Guo-hua;WEN Run-tao;CHEN Tian-di(School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;No.2 Geological Team,Jiangxi Bureau of Geology,Jiujiang 332000,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]江西省地质局第二地质大队,江西九江332000

出　　处：《矿物学报》2023年第4期501-511,共11页Acta Mineralogica Sinica

基　　金：江西省科学技术厅国家科技奖后备项目培育计划(编号:20203AEI91004);江西省地质勘查基金项目(编号:20200022)。

摘　　要：赣北香炉山矿床是江南世界级钨矿带北缘的特大型钨矿床,包含香炉山—形坪、大岩下和张天罗等3个相邻矿段。香炉山—形坪矿段主要由沿寒武系杨柳岗组泥质灰岩与黑云母花岗岩的接触带分布的透镜状和层状钨矿体组成,以矽卡岩型矿化为主;大岩下、张天罗矿段则主要由沿震旦系陡山沱组含炭质页(泥)岩与灯影组含炭含泥硅质岩顺层展布的钨矿体组成,矿化类型为角岩型。采自大岩下矿段含石英脉钨矿石中的石英H、O同位素结果显示,氧化物阶段石英δD_(V-SMOW)值为-67.9‰~-78.0‰、δ^(18)O_(H2O)值为-3.3‰~0.7‰;石英硫化物阶段石英δD_(V-SMOW)值为-64.6‰~-66.4‰、δ^(18)O_(H2O)值为-7.5‰~-0.3‰,指示了香炉山钨矿床成矿流体为岩浆水与大气水的混合流体,在氧化物阶段就发生了大气降水的加入,在石英硫化物阶段大气水混合比例接近40%。采集自香炉山各矿段不同硫化物样品中的S同位素结果相近,δ^(34)S值主要为1.2‰~5.4‰,均符合矿床硫源以岩浆硫为主的特征。综合区域地质背景和已有研究提出,在早白垩世的区域伸展背景下,新元古代地层熔融形成的富含钨的岩浆上涌,形成的岩浆热液与不断加入的大气降水在近地表发生混合形成成矿流体并持续演化,与不同层位的含钙围岩发生交代,最终沉淀形成香炉山白钨矿床。The Xianglushan deposit in the northern part of Jiangxi Province,is one of giant tungsten deposits in the northwestern margin of the world-class Jiangnan tungsten metallogenic belt.It contains three adjacent subordinate oreblocks,named the Xianglushan-Xingping,Dayanxia and Zhangtianluo oreblocks.The Xianglushan-Xinping oreblock comprises mainly lenticular and stratiform-like skarn-type W orebodies in the contact between argillaceous limestone of the Cambrian Yangliugang Formation and a biotite granite pluton.The Dayanxia and Zhangtianluo oreblocks comprise hornfels-type W orebodies distributed mainly along the bedding of carbonaceous shales of the Sinian Doushantuo Formation and carbonaceous argillaceous siliceous rocks of the Sinian Dengying Formation.The H-O isotopic results of quartzs from tungsten ore samples in the Dayanxia oreblock show that the δ^(18)O_(H2O) and S_(Dv.sMow) values for fluids in quartzs of the early quartz-oxide stage range from-3.3‰ to 0.7‰ and from-67.9‰ to-78.0‰,respectively,while those of the late quartz-sulfide stage range from-7.5%to-0.3‰,and from-64.6‰ to-66.4‰,respectively.These H-0 isotopic signatures suggest that magmatic fluid and meteoric water were mixed to have formed the ore-forming fluids of both quartz-oxide and quartz-sulfide stages,with up to about 40‰f meteoric water in the ore-forming fluid of quartz-sulfide stage.Sulfides from various subordinate oreblocks of the Xianglushan deposit have very similar δ^(34) s values varying generally from 1.2‰ to 5.4‰ which are consistent with the characteristics of magmatic sulfur.Integrated with the regional geological background,previously published data,and our results,it is suggested that the initial ore-forming fluid was formed by the mxing of magmatic hydrothermal fluid,which was derived from the uplifting W-rich fertile magma formed by the partial melting of the Upper Proterozoic material under the regional extension background in the Early Cretaceous,and meteoric water near the earth surface.The evolved o

关 键 词：氢-氧-硫同位素 矽卡岩矿床 香炉山钨矿床 江南钨矿带 

分 类 号：P618.67[天文地球—矿床学] P597[天文地球—地质学]