大兴安岭中南段昌图锡力银铅锌锰多金属矿床成矿物质来源及矿床成因：来自S-Pb-C-O同位素的制约  

The sources of ore-forming materials and genesis of the Changtuxili Ag-Pb-Zn-Mn polymetallic deposit in the middle-southern segment of Da Hinggan Mountains:Constraints from S-Pb-C-O isotope geochemistry

作　　者：何鹏[1] 郭硕 张阔 张天福 苏航 马一行[3] HE Peng;GUO Shuou;ZHANG Kuo;ZHANG Tianfu;SU Hang;MA Yixing(China Geological Survey Tianjin Geological Survey Center, Tianjin, 300170;Heilongjiang Institute of Geological Survey, Haerbin, 150036;Development Research Center, China Geological Survey, Beijing, 100037)

机构地区：[1]中国地质调查局天津地质调查中心,天津300170 [2]黑龙江省地质调查研究总院,哈尔滨150036 [3]中国地质调查局发展研究中心,北京100037

出　　处：《地质学报》2019年第8期2037-2054,共18页Acta Geologica Sinica

基　　金：中国地质调查局项目(编号:DD20190038)资助的成果

摘　　要：昌图锡力银铅锌锰矿床位于内蒙古锡林郭勒盟东乌旗地区,是近年来在大兴安岭成矿带中南段锡林浩特—霍林郭勒铅-锌-银-铜-钼多金属成矿亚带上新发现的一处多金属矿床,填补了该区域的找矿空白。矿床主要赋矿地层为白音高老组中酸性火山熔岩夹火山碎屑岩建造,矿体呈脉状、透镜状,构造控矿作用明显,北西及北东向构造交汇处是成矿有利部位。热液成矿期可以划分为4个成矿阶段:石英-黄铁矿阶段、铅锌金属硫化物阶段、银矿物阶段、石英-碳酸盐阶段。为探讨昌图锡力多金属矿床成矿物质来源及矿床成因,开展了S、Pb、C、O同位素分析。测试结果表明:矿床中矿石硫化物的δ 34 S值为0. 6‰~4‰,呈塔式分布特征,表明硫的来源为相对单一的深源岩浆。矿石中Pb同位素 206 Pb/ 204 Pb值为18. 129~18. 177,平均值为18. 155;207 Pb/ 204 Pb值为15. 500~15. 561,平均值为15. 533;208 Pb/ 204 Pb值为37. 849~38. 049,平均值为37. 959,μ值变化范围为9. 3~9. 41,ω值变化范围为34. 69~35. 82,铅同位素组成及各项分析数据表明矿石铅为壳幔混合来源。昌图锡力矿床硫、铅同位素组成与大兴安岭中南段多金属矿床的相似性暗示它们可能具有类似的成矿物质来源。矿床中δ 13 CV- PDB 值为-6. 1‰^-7. 9‰,δ 18 OV- SMOW 值为+8. 7‰^+13. 2‰,指示碳同位素来源于深部岩浆,并且晚期成矿阶段受到低温蚀变作用的影响,菱锰矿的形成是由于温度降低以及水/岩反应的耦合作用所导致。依据赋矿围岩年代推测昌图锡力矿床成矿时代大约为130~140Ma,与大兴安岭中南段成矿高峰期相一致。矿床的形成是深部岩浆流体逐步演化的产物,岩浆活动为成矿作用提供了热动力及成矿物质,初步认为昌图锡力银铅锌锰多金属矿床成因类型属于浅成低温热液型多金属矿床。The Changtuxili Ag-Pb-Zn-Mn deposit, which is located in the Dongwuqi area of Xilin Gol League, Inner Mongolia, is a newly discovered polymetallic deposit in the Xilinhaote-Huolinguole Pb-Zn-Ag-Cu-Mo polymetallic metallogenic subzone of the middle and southern Da Hinggan Mountains polymetallic metallogenic belt. The discovery of the deposit fills the prospecting gap in the area. Ore-hosting strata contain one suite of intermediate-felsic volcanic lava intercalated with volcaniclastic rocks of the Baiyingaolao Group, with orebodies occurring as veins and lenticular by faults. The junction areas of NW and NE trending structures are favorable for mineralization. Hydrothermal mineralization can be divided into four stages: quartz-pyrite stage, lead zinc metal sulfide stage, silver mineral stage and quartz carbonate stage. Based on a detailed analysis of geological characteristics, this study carried out S,Pb, C and O isotopic analysis to understand the origin of ore-forming materials and genesis of the Changtuxili deposit. The ^34 S values of polymetallic ore range from 0. 6%~ 4 % and display characteristic of tower shaped distribution, indicating that the sulfur derived from relatively single magma source. The 206 Pb/ 204 Pb ratios of sulfide ores range from 18. 129 to 18. 177 (18. 155 on average), 207 P b/204 Pb from 15. 500 to 15. 561 (15. 533 on average), and 208 Pb/204 Pb 37. 849 to 38. 049 (37. 959 on average), indicating that lead isotope ratios are relatively stable. The ^ values vary from 9. 3 to 9. 41, while j values vary from 34. 69 to 35. 82. The Pb isotopic compositions and all analytical data indicate that the lead was mainly derived from the mixture of crust-mantle materials. The sulfur and lead isotopic compositions of the Changtuxili deposit show high similarity with that of the polymetallic deposits in the Da Hinggan Mountains, indicating that they may have similar source of metallogenic m aterial.汐 13 CV -PDB values of 6. 1 7. 9% and 汐 18 0 V -SM O W values of + 8 . 7%^+ 13. 2% indicate that th

关 键 词：同位素 成矿物质来源 矿床成因 银多金属矿床 大兴安岭中南段 

分 类 号：P618.2[天文地球—矿床学]