大兴安岭东北部多宝山矿集区二道坎银铅锌矿床磁铁矿地球化学特征  

Geochemical Characteristics of Magnetite in Erdaokan Ag-Pb-Zn Deposit,Duobaoshan Ore Concentration Area,Northeastern Great Xing’an Range

作　　者：李玉洁 李成禄 杨元江 袁茂文 李博文 苏航 Li Yujie;Li Chenglu;Yang Yuanjiang;Yuan Maowen;Li Bowen;Su Hang(China Mining Association,Beijing 100029,China;Natural Resources Survey Institute of Heilongjiang Province,Harbin 150036,China;School of Earth and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Heilongjiang Geology and Mining Investment Group Co.Ltd.,Harbin 150090,China)

机构地区：[1]中国矿业联合会,北京100029 [2]黑龙江省自然资源调查院,哈尔滨150036 [3]中国地质大学(北京)地球科学与资源学院,北京100083 [4]黑龙江省地矿投资集团有限公司,哈尔滨150090

出　　处：《吉林大学学报（地球科学版）》2023年第2期436-449,共14页Journal of Jilin University：Earth Science Edition

基　　金：黑龙江省国土资源科研项目(201603);国家自然科学基金项目(41872038)。

摘　　要：二道坎银铅锌矿床是近几年在大兴安岭东北部多宝山矿集区新发现的一个大型银铅锌矿床。矿区内共发育2条矿体,银品位最高达25516 g/t,并伴生有铅锌、锰矿产出(铅+锌平均品位为1.2%,锰平均品位为9.5%)。矿石主要赋存于上志留统—中泥盆统泥鳅河组中,以石英脉胶结的热液角砾岩矿石为主,岩石已遭受蚀变;矿石中金属矿物主要为磁铁矿、黝铜矿、方铅矿、闪锌矿、黄铁矿、黄铜矿等;成矿阶段可划分为黄铁矿-磁铁矿-石英阶段、沥青-含银多金属硫化物阶段和碳酸盐阶段;常见的热液蚀变类型主要为硅化、碳酸盐化及赤铁矿化等。本研究以二道坎银铅锌矿床中的磁铁矿为研究对象,利用LA-ICP-MS测试了磁铁矿中的稀土、微量元素,以探讨磁铁矿的成因信息。结果显示:磁铁矿中稀土元素总量w(∑REE)为(27.94~81.54)×10^(-6),LREE/HREE为2.77~67.31,表现为轻稀土元素相对富集、重稀土元素亏损的右倾模式;(La/Yb)N介于9.42~280.59之间,Eu/Eu^(*)基本小于1,Ce/Ce^(*)介于0.89~1.54之间,La/Sm介于1.29~97.54之间,Gd/Yb介于0.02~117.11之间,表明磁铁矿在形成过程中经历了氧化还原环境的变化。其他微量元素投图显示,二道坎银铅锌矿床中的磁铁矿具有岩浆热液成因特征。The Erdaokan Ag-Pb-Zn deposit is a newly discovered large-scale silver-lead-zinc deposit in the Duobaoshan ore concentration area in the northeastern Great Xing’an Range.There are two ore bodies developed in the mining area,with the highest Ag grade of 25516 g/t,accompanied by lead-zinc and manganese ore(the average grade of lead+zinc is 1.2%,and the average grade of manganese is 9.5%).The ores mainly occur in the Upper Silurian to Middle Devonian Niqiuhe Formation,mainly hydrothermal breccia ores cemented by quartz veins,and the rocks have been altered.The metal minerals in the ores are mainly magnetite,tetrahedrite,galena,speltzite,pyrite,chalcopyrite,etc.The metallogenic stages can be divided into pyrite-magnetite-quartz stage,bitumen-silver-bearing polymetallic sulfide stage and carbonate stage.The common types of hydrothermal alteration are mainly silicification,carbonation and hematite,etc.In this study,the magnetite in the Erdaokan Ag-Pb-Zn deposit was taken as the research object,and the trace and rare earth elements in magnetite were measured by LA-ICP-MS to explore the genetic information of magnetite.The results show that the total amount of rare earth elements w(∑REE)in magnetite is(27.94-81.54)×10^(-6),and LREE/HREE is 2.77-67.31,showing a right-dipping pattern of relative enrichment of light rare earth elements and depletion of heavy rare earth elements.(La/Yb)N is between 9.42-280.59.Eu/Eu^(*)is basically less than 1,Ce/Ce^(*)is between 0.89-1.54,La/Sm is between 1.29-97.54,and Gd/Yb is between 0.02-117.11,they indicate that the magnetite has undergone changes in the redox environment during the formation process.Other trace element diagrams show that the magnetite in the Erdaokan Ag-Zn-Pb deposit has the characteristics of magmatic-hydrothermal origin.

关 键 词：磁铁矿 地球化学 微量元素 稀土元素 二道坎银铅锌矿床 多宝山矿集区 

分 类 号：P59[天文地球—地球化学] P618[天文地球—地质学]