湖南锡矿山超大型锑矿床围岩蚀变元素迁移特征及定量计算研究  

Elemental Migration and Mass Balance Calculation of Wall Rock Alternation in the Xikuangshan Sb Deposit,Hunan Province

作　　者：弭希风 胡瑞忠[1,2] 付山岭 彭建堂 骆金诚[1] 陈应华 MI Xi-feng;HU Rui-zhong;FU Shan-ling;PENG Jian-tang;LUO Jin-cheng;CHEN Ying-hua(State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences, Guiyang 550081,China;College of Earth Sciences,University of Chinese Academy of Sciences,Beijing 100049, China;Key Laboratory of Non-ferrous Metals Metallogenic Prediction of the Ministry of Education ,School of Geosciences and Info-physics,Central South University,Changsha 410083,China)

机构地区：[1]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,贵阳550081 [2]中国科学院大学地球科学学院,北京100049 [3]中南大学地球科学与信息物理学院有色金属成矿预测教育部重点实验室,长沙410083

出　　处：《矿物岩石地球化学通报》2019年第1期103-113,共11页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金重点项目(41230316);国家重点基础研究发展计划项目(2014CB440900)

摘　　要：湖南锡矿山锑矿床是目前世界上已发现的最大的锑矿床,其硅化非常发育且与矿化关系密切,根据硅化蚀变程度的强弱,从围岩到矿石大致划分为4个带:灰岩→弱硅化灰岩→强硅化灰岩→矿石。为揭示锡矿山锑矿的成矿过程及成矿流体信息,利用Isocon标准化方法,以Al_2O_3为惰性组分,对各蚀变带围岩及矿石的主、微量元素进行质量平衡计算。结果表明,热液蚀变过程中,Si、Sb、Li和Bi等大量迁入,而Ca、Mg、Na和大离子亲石元素Sr、Ba、Rb等大量迁出;成矿热液呈酸性并富硅,其中Hg、As、Au、Tl等元素含量极低,这可能是导致锡矿山锑矿床矿种单一的原因之一。稀土元素除Eu外,其他元素未发生明显的活化迁移,水岩反应并未影响原岩的稀土元素配分模式;蚀变岩及矿石中的Eu负异常可能表明成矿过程是在相对还原的环境下进行的。The Xikuangshan Sb deposit is the largest Sb deposit in the world. The silicification alteration is well developed in the deposit,which is closely associated with Sb mineralization. According to the alteration degree of wall rocks,four alteration zones are identified,including fresh limestone,weakly silicified limestone,strongly silicified limestone and highgrade ores. In this study,we carried out detailed elemental migration characteristics of wall rocks and ores from different alteration zones in order to decipher the nature of ore-forming fluids and mineralization process. The Isocon method is used to calculate the mass balance and Al2O3 compositions are regarded as immobile component. New results show that the majority elements including Si,Sb,Li and Bi are brought into wall rocks by hydrothermal fluids,whereas elements such as Ca,Mg,Na,Sr,Ba,Rb are significantly extracted out. The ore-forming fluids are acidic and silicic-enriched. Extremely low contents of Hg,Au,Tl and As may be responsible for the simple mineral assemblage in the Xikuangshan Sb deposit.REEs,except Eu,are not activated and migrated in such process and the REE patterns remain unchanged. Both altered rocks and ores have negative Eu anomalies,indicating that the mineralization took place in relatively reduced environment.

关 键 词：热液蚀变 元素迁移 标准化Isocon法 锡矿山锑矿床 

分 类 号：P618.44[天文地球—矿床学]