大兴安岭中北段二道河铅锌银多金属矿床地质特征与成矿物质来源  

Geological characteristics and ore-forming material sources of the Erdaohe Pb-Zn-Ag polymetallic deposits in the northern-central part of the Greater Khingan Mountains

作　　者：衮民汕 吕新彪[2,3] 曾道国 李杰[2] 陈超[3] 李建阳 王华建 GUN Min-shan;LV Xin-biao;ZENG Dao-guo;LI Jie;CHEN Chao;LI Jian-yang;WANG Hua-jian(Institute of Geological and Mineral Exploration,Non-Ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou,Guiyang 550005,China;Faculty of Earth Resources,China University of Geosciences,Wuhan 430074,China;Institute of Geological Survey,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]贵州省有色金属和核工业地质勘查局地质矿产勘查院,贵州贵阳550005 [2]中国地质大学(武汉)资源学院,湖北武汉430074 [3]中国地质大学(武汉)地质调查研究院,湖北武汉430074

出　　处：《矿物学报》2021年第2期150-162,共13页Acta Mineralogica Sinica

基　　金：内蒙古地勘基金项目(编号:NMKD2014-23);国家自然科学基金项目(编号:U1812402)。

摘　　要：二道河矿床是近年来大兴安岭中北段新发现的一处大型矽卡岩型铅锌银多金属矿床。矿床成矿作用经历了早矽卡岩阶段、晚矽卡岩阶段、磁黄铁矿-黄铁矿-石英阶段、石英多金属硫化物阶段和石英-碳酸盐等5个阶段的演化。为探讨矿床成矿物质来源,本文对矿床主要金属硫化物、与成矿关系密切的花岗斑岩、闪长岩、中生代火山岩开展了S、Pb同位素分析。结果表明,矿床主要金属矿物δ34S分布范围为5.8‰~8.9‰,呈"塔式分布",与典型矽卡岩型铅锌矿床及区域典型铅锌矿床硫同位素组成相近,与花岗质岩石较相似,表明该矿床硫主要来自于深部岩浆热液体系,热液演化过程中与奥陶系海相地层进行了硫同位素交换。矿床硫同位素组成表现为δ34Spy>δ34SSp>δ34SCcp>δ34SGn,暗示主成矿阶段硫同位素分馏达到了平衡,计算得到各共存矿物对的平衡温度范围为227~382℃。该矿床矿石矿物具有高放射性壳源铅的特征,而花岗斑岩及闪长岩、中生代火山岩铅同位素则具低放射性铅特征,铅同位素数据均落入造山带演化线附近,构造图解中具有明显线性分布特征,表明其具有相同铅源及铅同位素演化特征,在Δγ-Δβ图解中均落入与岩浆作用有关的上地壳与地幔混合俯冲带铅源区。综上表明,矿床成矿物质具有多元组分的贡献,而矿石矿物与花岗斑岩及闪长岩铅同位素组成、μ值和Th/U比值都较为接近,综合矿床铅锌矿体主要产出于花岗斑岩、闪长岩与碳酸盐岩接触带的空间关系,反映其主要物质来源为燕山期中酸性侵入岩。The Erdahe deposit is a large skarn type Pb-Zn-Ag polymetallic deposit discovered in the northern-central part of the Greater Khingan Mountains in recent years.The mineralization of the deposit had undergone five evolution stages including the early skarn,late skarn,pyrrhotite-pyrite-quartz,quartz polymetallic sulfides,and quartz-carbonate stages.In order to discuss the source of metallogenic materials,S and Pb isotopes of the main metal sulfides,granite-porphyry,diorite,and Mesozoic volcanic rocks in the deposit have been analyzed in this paper.The results show that theδ34S values of major metal minerals in the deposit are ranged from 5.8‰to 8.9‰,with a tower shaped histogram.They are similar to the sulfur isotopic compositions of the typical skarn type lead-zinc deposits and the regional typical lead-zinc deposits,and are relatively similar to those of granotoids,indicating that the sulfur of the deposit could be mainly derived from the deep-seated magmatic-hydrothermal system.The sulfur isotope exchange occurred between the Ordovician marine strata and the evolved hydrothermal fluid.The sulfur isotopic compositions of sulfides of main-ore stage of the deposit are subsequently changed in order ofδ34Spy>δ34SSp>δ34SCcp>δ34SGn,indicating that the balance of sulfur isotopic fractionation has been reached in the main-ore stage of the deposit,with the calculated equilibrium temperatures of those co-existed mineral pairs of227-382℃.Lead isotopic compositions show that the lead of ore minerals was characterized with highly radioactive crustal lead,while the lead of granitic porphyry,diorite,and Mesozoic volcanic rocks was characterized with low radioactive lead.The lead isotopic data are all plotted in the vicinity of the evolution line of orogenic belt in the tectonic discrimination diagram with obvious linear distribution characteristics,indicating that they have the same lead source and lead isotope evolution characteristics.The lead data are all plotted into the lead source area of the mixed subduction z

关 键 词：S、Pb同位素 大兴安岭中北段 铅锌矿床 成矿物质 

分 类 号：P618.4[天文地球—矿床学] P597[天文地球—地质学]