大兴安岭成矿带南段大座子山铜多金属矿成矿时代及其地质意义  

Metallogenetic Epoch of the Dazuozishan Cu-Polymetallic Deposit in the Southern Part of the Great Hinggan Range Metallogenic Belt and Its Geological Significance

作　　者：唐昆 林淞[2] 康志宏 陈辉[3] 俞炳 张军成 扈德峰 王永彬 TANG Kun;LIN Song;KANG Zhihong;CHEN Hui;YU Bing;ZHANG Juncheng;HU Defeng;WANG Yongbin(Kunming Prospecting Design Institute of China Nonferrous Metals Industry Co.,Ltd.,Kunming,Yunnan 650051;Yunnan Key Laboratory of Earth System Science,Yunnan University,Kunming,Yunnan 650500;Development and Research Center,China Geological Survey,Beijing 100037;Chifeng Ruineng Mining Co.,Ltd,Chifeng,Inner Mongolia 024050)

机构地区：[1]中国有色金属工业昆明勘察设计研究院有限公司,云南昆明650051 [2]云南大学,云南省地球系统科学重点实验室,云南昆明650500 [3]中国地质调查局发展研究中心,北京100037 [4]赤峰锐能矿业有限公司,内蒙古赤峰024050

出　　处：《地质与勘探》2024年第6期1095-1104,共10页Geology and Exploration

基　　金：国家自然科学基金(编号:42162009);云南省基础研究计划项目-重点项目(编号:202201AS070004);中地调研项目(编号:[2023]34)联合资助。

摘　　要：内蒙古自治区大座子山矿床是大兴安岭成矿带南段近年来新发现的铜多金属矿床。该矿床矿体产于上侏罗统满克头鄂博组流纹岩内,成矿过程可以划分为白色石英-少硫化物(黄铁矿)阶段、烟灰色石英-多硫化物(黄铁矿、闪锌矿、方铅矿、黄铜矿和辉钼矿)阶段和方解石-硫化物(黄铁矿、方铅矿和闪锌矿)阶段。本次研究通过对石英-多金属成矿阶段辉钼矿开展Re-Os定年,获得6个辉钼矿模式年龄为134.4~136.9 Ma,加权平均值为135.5±0.8 Ma,与^(187)Re-^(187)Os等时线年龄(136.2±3.2 Ma)一致,表明其形成于早白垩世,不同于前人依据地层厘定的成矿时代。辉钼矿中Re含量为44.31×10^(-6)~92.93×10^(-6),介于壳幔源区之间,推断成矿物质为壳幔混合来源。结合区域构造-岩浆演化,推断大座子山铜多金属矿床形成于鄂霍茨克洋闭合后陆内垮塌与古太平洋板块后撤-回卷联合作用诱发的伸展背景。The Dazuozishan deposit in Inner Mongolia is a recently discovered Cu-polymetallic deposit in the southern part of the Great Hinggan Range metallogenic belt.The orebodies in this deposit occurred in the rhyolite of Upper Jurassic Manketouebo Group,and the mineralization process was divided into three stages,i.e.,white quartz-minor sulfide stage(pyrite)stage,smoky quartz-polymetallic sulfide(pyrite,sphalerite,galena,chalcopyrite and molybdenite)stage and calcite-sulfide stage(pyrite,sphalerite and galena).This work conducted Re-Os dating of six molybdenite samples from the quartz-polymetallic sulfide mineralization stage,and obtained 134.4 to 136.9 Ma of model age with a weighted average age of 135.5±0.8 Ma.These ages are consistent with the^(187)Re-^(187)Os isochronous age of 136.2±3.2 Ma.It is indicated that the Dazuozishan Cu-polymetallic deposit was formed in the Early Cretaceous,which was different from the previous age constrained by the Manketouebo rhyolite.Moreover,the Re content of the molybdenite ranged from 44.31×10^(-6)to 92.93×10^(-6),plotted between the crustal and mantle source regions.It is inferred that the ore-forming materials were derived from mixed crustal and mantle source.Based on the regional tectonic and magmatic evolution,the Dazuozishan copper polymetallic deposit was formed under extensional setting triggered by joint interactions between post-orogenic continental collapse of the Mongol-Okhotsk Ocean,and retreat and rollback of the Paleo-Pacific Ocean slab.

关 键 词：辉钼矿 RE-OS定年 成矿时代 早白垩世 大座子山铜多金属矿 大兴安岭成矿带 

分 类 号：P618[天文地球—矿床学]