河北东坪碲金矿床辉钼矿Re-Os及锆石U-Pb年龄研究  

Study on molybdenite Re-Os and zircon U-Pb ages of the Dongping tellurium-gold deposit in Hebei Province

作　　者：王大钊 刘家军[2,3] 翟德高[2,3] 甄世民[3,4,5] 王江[2,3] WANG Dazhao;LIU Jiajun;ZHAI Degao;ZHEN Shimin;WANG Jiang(State Key Laboratory of Nuclear Resource and Environment,East China University of Technology,Nanchang 330013,China;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(Beijing),Beijing 100083,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Development and Research Center,China Geological Survey,Beijing 100037,China;Technical Guidance Center for Mineral Resources Exploration,Ministry of Natural Resources,Beijing 100083,China)

机构地区：[1]东华理工大学核资源与环境国家重点实验室,江西南昌330013 [2]中国地质大学(北京)地质过程与矿产资源国家重点实验室,北京100083 [3]中国地质大学(北京)地球科学与资源学院,北京100083 [4]中国地质调查局发展研究中心,北京100037 [5]自然资源部矿产勘查技术指导中心,北京100083

出　　处：《地学前缘》2020年第2期405-419,共15页Earth Science Frontiers

基　　金：国家自然科学基金项目(41730426,41030423)。

摘　　要：东坪碲金矿床是与碱性侵入岩有关的国内规模最大的碲金矿床。虽然前人已对该矿床做过大量研究,但其成矿年龄仍存在较大争议。文章通过对矿床中辉钼矿Re-Os和锆石U-Pb年龄进行研究,对成矿年龄和矿床成因进行限定。矿床中的辉钼矿存在浸染状和细脉状两种产状。浸染状辉钼矿通常产于正长岩,与硫化物共生,Re-Os模式年龄为(401.1±2.1)和(402.8±2.1) Ma。细脉状辉钼矿主要产在石英-硫化物脉中,其内部及裂隙中产出大量自然金,Re-Os模式年龄为(380.3±2.0)和(376.9±2.9) Ma。含金石英脉中的岩浆锆石U-Pb年龄为(394±1.7) Ma,热液锆石U-Pb年龄为(382±4.7) Ma。辉钼矿与锆石年龄-致,且与水泉沟碱性杂岩体侵位年龄相吻合,因此认为东坪碲金矿床存在泥盆纪成矿,可能与水泉沟岩体岩浆活动有关。矿床经历了晚侏罗世-早白垩世岩浆流体的交代、活化、富集过程,最终形成大型碲金矿床。矿床中的碲主要来自上地幔或洋壳物质的部分熔融,水泉沟碱性岩浆出溶的高氧逸度、中偏碱性的流体和脱气作用为碲的迁移和富集提供了重要条件。The Dongping tellurium-gold(Te-Au)deposit is the largest alkaline pluton-related Te-Au deposit in China.Although many studies have been conducted on the deposit,its geochronology and genesis remain controversial.In this paper,we report on molybdenite Re-Os and zircon U-Pb ages to determine the timing and genesis of the Dongping Te-Au deposit.Two types of molybdenite have been identified.The disseminated molybdenite often co-exists with sulfides in syenite.Two disseminated molybdenite samples yield model ages of401.1±2.1 and 402.8±2.1 Ma.The vein-type molybdenite contains native gold grains and occurs as aggregations or veinlets in quartz-sulfide veins.Two aggregated samples show model ages of 380.3±2.0 and 376.9±2.9 Ma.Magmatic zircons collected from quartz veins yield a crystallization age of 394±1.7 Ma,while the hydrothermal zircons are dated as 382±4.7 Ma.We argue that a Devonian mineralization stage existed in the Dongping Te-Au deposit,which was related to the magmatic-hydrothermal activity of the Shuiquangou alkaline complex.The deposit underwent metasomatism,activation,and enrichment processes driven by late Jurassic to early Cretaceous hydrothermal events,which eventually produced this large Te-Au deposit.Tellurium in Dongping deposit was mainly derived from partial melting of upper mantle and oceanic materials.Fluid exsolution and degasification of the Shuiquangou alkaline magma generated high oxygen fugacity medium-to meta-alkalic hydrothermal fluids and vapors,which are helpful for tellurium migration and enrichment.

关 键 词：东坪碲金矿床 辉钼矿RE-OS年龄 锆石U-PB年龄 碲超常富集 张家口地区 

分 类 号：P618.83[天文地球—矿床学] P618.51[天文地球—地质学]