内蒙古二道河铅锌银矿床成矿流体、物质来源及成因探讨  

Discussion on the ore-forming fluids,materials sources and genesis of Erdaohe Pb-Zn-Ag deposit,Inner Mongolia

作　　者：焦天龙 李进文[1] 郭向国 佘宏全[1] 任程昊 李长俭 JIAO Tianlong;LI Jinwen;GUO Xiangguo;SHE Hongquan;REN Chenghao;LI Changjian(Chinese Academy of Geological Sciences,Beijing 100037,China;Inner Mongolia University of Technology,Huhhot 010051,Inner Mongolia,China)

机构地区：[1]中国地质科学院,北京100037 [2]内蒙古工业大学,内蒙古呼和浩特010051

出　　处：《中国地质》2024年第2期426-442,共17页Geology in China

基　　金：国家重点研发计划(2017YFC0601303)资助。

摘　　要：【研究目的】二道河铅锌银矿位于大兴安岭中段,是近年来发现的具有代表性的大型矽卡岩型矿床,通过对该矿床成因的研究将有助于指导大兴安岭中段多金属矿床的勘查工作。【研究方法】本文在野外地质调查的基础上,选取各成矿阶段热液石英进行流体包裹体研究,并结合矿石S、Pb同位素与方解石C、O同位素,探讨该矿床成矿流体及物质来源。【研究结果】二道河矿床先后经历了矽卡岩阶段、石英硫化物阶段、石英碳酸盐阶段。测温结果显示,热液石英中的包裹体以气液两相为主,矽卡岩阶段石英中包裹体均一温度为310~435℃,盐度为11.7%~0.71%NaCleqv;石英-硫化物阶段石英中包裹体均一温度为195~310℃,盐度为12.9%~0.35%NaCleqv;石英-碳酸盐阶段石英中包裹体均一温度为148~195℃,盐度为4.18%~0.35%NaCleqv。方解石C、O同位素显示矿床经历了水岩反应,并有大气降水的加入。矿石硫同位素δ^(34)S为5.4‰~10.0‰,来源于岩浆与地层的混合硫;铅同位素特征参数表明,铅的来源与造山相关的岩浆作用有关,以上地壳铅为主并混合了少量的深源铅。【结论】综上所述,二道河铅锌银矿的成矿流体与物质来源应与蒙古—鄂霍茨克洋闭合造山后伸展导致的大规模岩浆作用有关。[Objective]The Erdaohe silver-lead-zinc deposit is located in the middle section of the Greater Khingan Range.It is a representative large-scale skarn-type deposit discovered in recent years.Studying the origin of this deposit will help guide the exploration of polymetallic deposits in the middle section of the Greater Khingan Range.[Methods]On the basis of field geological survey,this paper made research on the fluid inclusion in the keatite selected at each stage of mineralization,and discussed the ore-forming fluid and material sources in combination with the S and Pb isotopes of ore and the C and O isotopes of calcite.[Results]The research result showed the formation of the deposit throughout the process from the skarn stage to the quarte-sulfide stage and to the quartz carbonate stage.According to the temperature measurement result,the inclusion in keatite was mainly characterized by gas-liquid phase,with the homogenization temperature of 310-435℃at the skarn stage,195-310℃at the quarte-sulfide stage and 148-195℃at the quartz carbonate stage,and the salinity of 11.7%-0.71%NaCleqv at the skarn stage,12.9%-0.35%NaCleqv at the quartz-sulfide stage and 4.18%-0.35%NaCleqv at the quartz-carbonate stage.The C and O isotopes of calcite indicated a water-rock reaction of the deposit,in which atmospheric precipitation was found.Theδ^(34)S value of the S isotope of ore was 5.4‰-10.0‰from a mixture of sulfurs in magma and strata;as per the characteristic parameter of lead isotope,the source of lead was associated with the orogeny-related magmatism,where the lead was mostly from the upper crust,and slightly from the deep source.[Conclusions]Accordingly,the ore-forming fluid and material sources were considered the products of the large-scale magmatism caused by the extension after the closure of Mongolia-Okhotsk for orogeny.

关 键 词：二道河铅锌银矿床 流体包裹体 硫、铅、碳、氧同位素 物质来源 成矿流体 矿床成因 矿产勘查工程 内蒙古 

分 类 号：P611[天文地球—矿床学]