贵州水银洞卡林型金矿床方解石稀土元素地球化学特征与找矿意义  

Characteristics of race earth elements of calcites from the Shuiyindong Carlin-type gold deposit,Guizhou,China and their exploration implication

作　　者：徐碧良 谭亲平 夏勇[2] 赵亦猛 陈明[3] 王泽鹏[3] XU Bi-liang;TAN Qin-ping;XIA Yong;ZHAO Yi-meng;CHEN Ming;WANG Ze-peng(Guizhou Zijin Mining Co.Ltd,Zhenfeng 562200,China;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China;No.105 Geological Team,Guizhou Bureau of Geology and Mineral Exploration and Development,Guiyang 550018,China)

机构地区：[1]贵州紫金矿业股份有限公司,贵州贞丰县562200 [2]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550081 [3]贵州省地质矿产勘查开发局一○五地质大队,贵阳550018

出　　处：《矿物学报》2020年第6期685-694,共10页Acta Mineralogica Sinica

基　　金：国家重点研发计划“穿透性地球化学勘查技术”(编号:2016YFC0600607);国家自然科学基金项目(编号:41803046);贵州省教育厅青年科技人才成长项目(编号:黔教合KY字(2016)229);贵州省科技计划项目(编号:黔科合基础[2019]1138号)。

摘　　要：水银洞是滇黔桂地区最大的、隐伏的、层控型卡林型金矿床。本文以水银洞金矿床为例,采集矿体裂隙、无矿围岩、断层破碎带、中上二叠统之间构造蚀变体和远离水银洞金矿床无矿区域地表裂隙等5种空间部位中的方解石,分析其稀土(REE)和As、Sb、Tl、Y等微量元素组成,以期能揭示成矿流体地球化学信息,并挖掘方解石用于滇黔桂地区隐伏矿找矿的地球化学指标。矿体裂隙中充填的与成矿作用相关的方解石具有中稀土(MREE)富集的配分模式和正Eu异常(δEu=1.01~1.51)的显著特征,显示了成矿流体是一种MREE相对富集,超常富Eu的还原性流体。其它空间部位方解石的REE配分模式和Eu异常特征(δEu=0.60~1.58)复杂多样,显示了这些方解石的多来源性、多期性和复杂性。不同空间部位方解石的As、Sb、Tl含量没有明显的区别,无法根据成矿相关元素(如As、Sb、Tl等)含量的高低,识别其与成矿作用的关系。在?MREE-δEu和Y/Ho-La/Ho图解中,矿体裂隙中的方解石可与其它空间部位的方解石区分,可大致判断方解石与成矿作用的相关性。成矿流体在经历Au沉淀成矿作用后,可能沿着各种断裂和微裂隙继续运移,甚至直达地表。方解石REE组成,为滇黔桂地区金矿隐伏矿找矿提供了一种新的指标。The Shuiyindong deposit is the largest,concealed,strata-bound Carlin-type gold deposit in the Yunnan-Guizhou-Guangxi region in southwestern China.In this paper,calcites located in five different spatial positions(e.g.fissures of ores,wall rocks,fault zones,altered structural zone of the unconformity between Middle and Upper Permian strata at the Shuiyindong gold deposit,and fissures of surficial unmineralized rocks far away from the Shuiyindong deposit)were collected to analyze their contents of race earth elements(REE),As,Sb,Tl,and Y,in order to reveal the geochemical information of ore-forming fluids,and to explore applicable geochemical indicators of clacites for prospecting concealed gold ore bodies in the Dian-Qian-Gui area.Calcites associated with gold mineralization in fissures/fractures of ore bodies have obviously MREE-enriched distribution patterns with positive Eu anomalies(δEu=1.01-1.51),indicating that the ore-forming fluid could be a relatively MREE enriched and Eu superabundant reductive fluid.The REE patterns and Eu anomalies(δEu=0.60~1.58)of the calcites from other four spatial positions are complex and diverse,showing multi-source,multi-phase,and complexity of those calcites.There is no obvious difference among contents of As,Sb,and Tl of calcites from different spatial locations.It is hard to identify if there is relationship between the gold mineralization and the contents of ore-related elements(such as As,Sb,Tl,etc.)of calcites.In the?MREE-δEu and Y/Ho-La/Ho diagrams,the calcites in fissures of ores can be distinguished from the calcites occurred in other spatial positions.Thus,these two diagrams can be used to discriminate if the calcites are related to the gold mineralization.It is believed that after the gold precipitation from the ore-forming fluid,the evolved fluid could further continuously migrate along various faults and micro-cracks to the relatively shallow level,and even to the surface of the crust.Therefore,REE characteristics of calcites can be used as a new indicator for pro

关 键 词：水银洞 卡林型金矿 方解石 稀土元素 

分 类 号：P612[天文地球—矿床学] P632[天文地球—地质学]