大兴安岭东北部永新金矿床金银系列矿物和碲化物的发现及其意义  

Discovery and geological significance of gold-silver bearing minerals and tellurides in the Yongxin gold deposit in the northeastern Great Xing'an Range

作　　者：李成禄 于援帮 袁茂文 李胜荣[2] 徐文喜 朱静[3] 李士胜 LI Chenglu;YU Yuanbang;YUAN Maowen;LI Shengrong;XU Wenxi;ZHU Jing;LI Shisheng(Heilongjiang Institute of Geological Survey,Harbin 150036,China;China University of Geosciences(Beijing),Beijing 100083,China;Bureau of Geology and Mineral Resource of Heilongjiang Province,Harbin 150036,China)

机构地区：[1]黑龙江省地质调查研究总院,黑龙江哈尔滨150036 [2]中国地质大学(北京),北京100083 [3]黑龙江省地质矿产局,黑龙江哈尔滨150036

出　　处：《地学前缘》2020年第4期244-254,共11页Earth Science Frontiers

基　　金：国家自然科学基金项目(41872038);黑龙江省国土资源科研项目(黑国土科研201603)和公益项目(DZKC-GY-2018003)。

摘　　要：永新金矿床是早白垩世晚期形成的浅成低温热液型金矿床。对其主要金银系列矿物和碲化物研究显示:金银系列矿物中Au质量分数为65.092%~90.713%(平均为83.942%),Ag为5.652%~16.632%(平均为11.285%);以自然金和银金矿为主,成色集中在870.2~941.3(平均为881.1),主要以包体金、粒间金和裂隙金的形式存在,粒径集中在10~20μm;碲化物主要有辉碲铋矿、碲金银矿、碲银矿和碲铅矿等,以碲银矿数量最多,主要包裹于黄铁矿内部或产于裂隙中,常与自然金和方铅矿连生,粒径多为5~20μm。综合研究碲化物组合特征、不同标高金矿物的成色、Te/Au值等认为,永新金矿床碲化物形成时成矿流体的lgf(Te2)介于-15.2^-9.4范围,lgf(S2)介于-16.7^-14.0范围,矿床与火山或次火山热液有关,具备中浅成成矿特征,深部尚有较大成矿潜力。The Yongxin gold deposit,formed during the Early Cretaceous,is an epithermal type deposit.We performed EPMA analysis which showed that the Au-Ag bearing minerals in the Yongxin gold deposit contained 65.092%-90.713%(mass fraction)Au(averaged at 83.942%)and 5.652%-16.632%Ag(averaged at 11.285%).The gold deposit mainly contained 10-20μm natural gold and electrum grains(fineness ranged from 870.2 to 941.3 with an average of 881.1)occurring in inclusions,intergranular pores and crevices.Telluride is mainly composed of tetradymite,petzite,hessite and altaite.Hessite(5-20μm)is the most common telluride in the Yongxin gold deposit,occurring in the interior or fracture of pyrite grains often associated with natural gold and galena.We studied telluride assemblage,fineness of gold and Te/Au values at different elevation.The results showed that the lgf(Te2)and lgf(S2)values during telluride formation ranged from-15.2 to-9.4 and from-16.7 to-14.0,respectively,which revealed that the mineralization in the Yongxin gold deposit is associated with volcanic or subvolcanic hydrothermal fluid and with characteristics of shallow mineralization,suggesting great mineralization potential still at depth.

关 键 词：化学成分 金银系列矿物 碲化物 永新金矿 大兴安岭东北部 

分 类 号：P578.11[天文地球—矿物学] O612.6[天文地球—地质学]