贵州半边街锗锌矿床锗的富集特征及其地质意义  

The enrichment characteristics of germanium and it's geological significance in the Banbianjie Ge-Zn deposit,Guizhou

作　　者：程涌 周家喜 孙国涛 黄智龙[6] CHENG Yong;ZHOU JiaXi;SUN GuoTao;HUANG ZhiLong(Key Laboratory of Critical Minerals Metallogeny in Universities of Yunnan Province,School of Earth Sciences,Yunnan University,Kunming 650500,China;Faculty of Metallurgy and Mining Engineering,Kunming Metallurgy College,Kunming 650033,China;Yunnan Key Laboratory of Sanjiang Metallogeny and Resources Exploration&Utilization,Yunnan University,Kunming 650500,China;MNR Key Laboratory of Sanjiang Metallogeny and Resources Exploration&Utilization,Yunnan University,Kunming 650500,China;College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China)

机构地区：[1]云南大学地球科学学院,云南省高校关键矿产成矿学重点实验室,昆明650500 [2]昆明冶金高等专科学校冶金与矿业学院,昆明650033 [3]云南省三江成矿作用及资源勘查利用重点实验室,昆明650500 [4]自然资源部三江成矿作用及资源勘查利用重点实验室,昆明650500 [5]贵州大学资源与环境工程学院,贵阳550025 [6]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

出　　处：《岩石学报》2024年第1期43-59,共17页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(42172082、U1812402);云南大学科研启动项目(YJRC4201804);云南大学关键金属成矿与找矿预测创新团队项目(2021-3);贵州找矿突破战略行动重大协同创新项目([2022]ZD004);云南省教育厅科学研究基金(2022J1304)联合资助.

摘　　要：锗(Ge)属于战略性关键矿产资源,是众多高新技术领域的重要原材料。Ge主要以共/伴生形式产出于Zn、Pb和Cu等热液贱金属矿床和煤矿床中,目前全球Ge资源主要来源于铅锌矿的副产品。近期取得较大找矿突破的半边街锌矿床(7.70Mt矿石,Zn平均品位5.1%)伴生有超大型规模的金属Ge(>900t@110×10^(-6)),然而Ge超常富集的机制不清。本次研究利用LA-ICPMS对闪锌矿进行了微区原位微量元素组成和Mapping分析,以揭示Ge等元素的富集特征、赋存状态和替代方式,探讨Ge的富集机制。分析结果表明,半边街矿床闪锌矿中高含量(平均值>100×10^(-6))微量元素有Fe、Pb、Ge和Cd等,较高含量(平均值100×10^(-6)~10×10^(-6))的有Mn、Ga、Sn和Tl,以及较低含量(平均值<10×10^(-6))的有Ag、Cu、In和Sb。相比于各类型铅锌矿床,半边街闪锌矿Ge超常富集(274×10^(-6)~1938×10^(-6),平均为1055×10^(-6),达到1000倍富集)。该矿床中Ge以类质同象或纳米颗粒形式赋存于闪锌矿中。微量元素摩尔量相关性图揭示Ge替代Zn的方式以Ge^(4+)+Pb^(2+)3Zn^(2+)为主,其次为nGe^(4+)+Mn 2+(2n+1)Zn^(2+)和nGe^(4+)+2Tl^(3+)(2n+3)Zn^(2+)。综合分析认为,半边街矿床Ge可能来源于相对富Ge的前寒纪基底;富有机质的盆地流体在Ge的搬运中发挥重要作用;Ge、Cd等稀散元素的共生分异制约了Ge的最终超常富集。因此,半边街矿床中Ge的超常富集是“源、运、聚”复杂过程多要素耦合作用的结果。Germanium(Ge)is a strategic and critical mineral resource,and an important raw material for many high-tech fields.Germanium is mainly produced as a by-product of hydrothermal base metal deposits such as Zn,Pb and Cu,as well as coal deposits.The Banbianjie Zn deposit(7.70Mt ores,with an average Zn grade of 5.1%),which has recently made significant breakthroughs in mineral exploration,is accompanied by ultra large-scale metal Ge(>900t@110×10^(-6)).However,the mechanism of Ge super-enrichment is unclear.In this study,we used LA-ICPMS to conduct sphalerite in-situ trace elements and mapping analyses,aiming to elucidate the occurrence and substitution of Ge and other dispersed elements.The results reveal that high concentrations(average>100×10^(-6))trace elements in sphalerite from the Banbianjie deposit is characterized by Fe,Pb,Ge and Cd,relatively high concentrations(average 100×10^(-6)-10×10^(-6))trace elements are Mn,Ga,Sn and Tl,and the low concentrations(average value<10×10^(-6))trace elements are Ag,Cu,In and Sb.Compared with other types of Pb-Zn deposits,The sphalerite from Banbianjie shows exceptional Ge enrichment(274×10^(-6)~1938×10^(-6),average 1055×10^(-6)).LA-ICPMS time-resolved depth profile and micro-area mapping analysis demonstrate that Ge occurs in sphalerite in an isomorphic or nanoparticle manner.Trace element molar correlation diagrams suggest that Ge substitutes Zn predominantly by Ge^(4+)+Pb^(2+)3Zn^(2+),followed by nGe^(4+)+Mn 2+(2n+1)Zn^(2+)and nGe^(4+)+2Tl^(3+)(2n+3)Zn^(2+).Based on comprehensive analysis,it is believed that the Ge in the Banbianjie deposit may have originated from a relatively Ge rich Precambrian basements;Organic basin fluids play an important role in the transport of Ge;The symbiotic differentiation of rare and dispersed elements such as Ge and Cd restricts the ultimate supernormal enrichment of Ge.Therefore,the supernormal enrichment of Ge in the Banbianjie deposit is the result of the complex process of“source,transport,and accumulation”and the coupling of

关 键 词：微量元素 闪锌矿 锗(Ge) 替代机制 半边街锗锌矿床 

分 类 号：P595[天文地球—地球化学] P618.75[天文地球—地质学]