小秦岭金矿田桐沟金矿床黄铁矿微量元素组成及其成因意义  

Trace elements composition of pyrite in Tonggou Gold Deposit,Xiaoqinling Gold Field and its genetic significance

作　　者：郝建瑞 王义天[1,2] 刘俊辰 胡乔青 张向卫[4] 李满军 Hao Jianrui;Wang Yitian;Liu Junchen;Hu Qiaoqing;Zhang Xiangwei;Li Manjun(Institute of Mineral Resources,Chinese Academy of Geological Sciences;MNR Key Laboratory of Metallogeny and Mineral Assessment;School of Earth Science and Resources,China University of Geosciences,Beijing;Lingbao Jinyuan Mining Industry Co.,Ltd.)

机构地区：[1]中国地质科学院矿产资源研究所 [2]自然资源部成矿作用与资源评价重点实验室 [3]中国地质大学(北京)地球科学与资源学院 [4]灵宝金源矿业股份有限公司

出　　处：《黄金》2021年第8期8-16,共9页Gold

基　　金：国家重点研发计划项目(2016YFC0600106);中央级公益性科研院所基本科研业务费项目(KK2104)。

摘　　要：位于华北克拉通南缘的小秦岭金矿田是中国第二大黄金产地,其矿化类型以石英脉型为主。桐沟金矿床是小秦岭金矿田内典型石英脉型金矿床,其成矿过程可分为4个阶段:黄铁矿-石英阶段(Ⅰ)、石英-黄铁矿阶段(Ⅱ)、石英-多金属硫化物阶段(Ⅲ)和石英-碳酸盐阶段(Ⅳ)。矿石矿物主要有黄铁矿、黄铜矿、方铅矿、闪锌矿、磁黄铁矿、自然金。此外,还发育碲铋矿、碲铅矿等与金共生的碲化物。主要的矿石矿物黄铁矿可分为3个世代(Py1、Py2和Py3),分别对应前3个成矿阶段。黄铁矿原位微区LA-ICP-MS微量元素分析结果显示:各世代黄铁矿中普遍贫As,Py1中Au、Ag、Te和Bi含量较低且常低于检出限,Py2和Py3中Au、Ag、Te和Bi含量则显著升高且含量差异较大。碲化物特征及黄铁矿微量元素组成表明:Ⅱ、Ⅲ成矿阶段是主要矿化阶段,Py2和Py3中Au与Te、Bi存在显著的正相关关系,指示金矿化与Te、Bi关系密切。Te、Bi的异常富集,指示了成矿流体可能来自深部岩浆的脱挥发分或地幔脱气作用。Situated in the southern margin of the North China Craton,the Xiaoqinling Gold Field is the second largest gold production region in China,and its mineralization type is mainly quartz vein type.The Tonggou Gold Deposit is a typical quartz vein type gold deposit in the Xiaoqinling Gold Field,whose mineralization process can be divided into four stages:pyrite-quartz stage(Ⅰ),quartz-pyrite stage(Ⅱ),quartz-polymetallic sulfides stage(Ⅲ)and quartz-carbonate stage(Ⅳ).Ore minerals mainly include pyrite,chalcopyrite,galena,sphalerite,pyrrhotite and natural gold.Additionally,tellurides associated with gold,such as tellurobismuthite and altaite,are also developed.The main ore mineral pyrite can be divided into three generations(Py1,Py2 and Py3),corresponding to the first three mineralization stages respectively.In-situ LA-ICP-MS analysis of trace elements in pyrite shows that As is generally poor in pyrite of different generations.The contents of Au,Ag,Te and Bi in Py1 are low and often below detection limit,while Py2 and Py3 exhibit distinguished compositions and are significantly enriched in Au,Ag,Te and Bi.The tellurides and trace elements composition of pyrite indicate that StageⅡandⅢare the main mineralization stages.There is a significant positive correlation between Au and Te,Bi in Py2 and Py3,implying that the gold mineralization is closely related to Te and Bi.The abnormal enrichment of Te and Bi indicates that the ore-forming fluid may have come from the deep magma devolatilization or mantle degassing.

关 键 词：黄铁矿微量元素组成 碲化物 原位微区LA-ICP-MS微量元素分析 桐沟金矿床 小秦岭金矿田 

分 类 号：TD11[矿业工程—矿山地质测量] P618.51[天文地球—矿床学]