地学前缘 ›› 2020, Vol. 27 ›› Issue (2): 405-419.DOI: 10.13745/j.esf.sf.2020.3.29

• 矿床地质地球化学 • 上一篇    下一篇

河北东坪碲金矿床辉钼矿Re-Os及锆石U-Pb年龄研究

王大钊,刘家军,翟德高,甄世民,王江   

  1. 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
  • 收稿日期:2019-11-15 修回日期:2019-12-18 出版日期:2020-03-25 发布日期:2020-03-25
  • 作者简介:王大钊(1991—),男,博士,讲师,主要从事矿床学研究。E-mail:dazhaowang@foxmail.com
  • 基金资助:

    国家自然科学基金项目(41730426,41030423)

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

WANG Dazhao,LIU Jiajun,ZHAI Degao,ZHEN Shimin,WANG Jiang   

  1. 1. State Key Laboratory of Nuclear Resource and Environment, East China University of Technology, Nanchang 330013, China
    2. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Beijing), Beijing 100083, China
    3. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
    4. Development and Research Center, China Geological Survey, Beijing 100037, China
    5. Technical Guidance Center for Mineral Resources Exploration, Ministry of Natural Resources, Beijing 100083, China
  • Received:2019-11-15 Revised:2019-12-18 Online:2020-03-25 Published:2020-03-25

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。辉钼矿与锆石年龄一致,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。

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

Abstract:

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 of 401.1±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.

Key words: Dongping telluriumgold deposit, molybdenite Re-Os age, zircon U-Pb age, tellurium superenrichment, Zhangjiakou district

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