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现代地质 ›› 2020, Vol. 34 ›› Issue (05): 1092-1102.DOI: 10.19657/j.geoscience.1000-8527.2020.05.20

• 矿床学 • 上一篇    

大兴安岭大洋山钼矿成矿岩体地球化学、锆石U-Pb年龄及构造背景

杨元江1(), 李成禄1, 邓昌州2, 李文龙1, 张立1, 赵忠海3(), 赵寒冬1   

  1. 1.黑龙江省自然资源调查院,黑龙江 哈尔滨 150036
    2.中国科学院 地球化学研究所,贵州 贵阳 550081
    3.辽宁工程技术大学 矿业学院,辽宁 阜新 123000
  • 收稿日期:2020-03-23 修回日期:2020-07-19 出版日期:2020-10-28 发布日期:2020-10-29
  • 通讯作者: 赵忠海
  • 作者简介:赵忠海,男,副教授,1984年出生,矿物学、岩石学、矿床学专业,主要从事区域地质调查及矿床学研究工作。Email: zhaozhonghai@lntu.edu.cn
    杨元江,男,高级工程师,1982年出生,地质学专业,主要从事地质矿产勘查工作。Email: geolj@qq.com
  • 基金资助:
    黑龙江省国土资源公益项目(GY-2018003);黑龙江省地质矿产局科研项目(黑地矿科研2019-1);辽宁省自然科学基金项目(2020-BS-258)

Geochemistry, Zircon U-Pb Dating and Tectonic Setting of the Granitoid Related with the Dayangshan Molybdenum Deposit, Daxinganling

YANG Yuanjiang1(), LI Chenglu1, DENG Changzhou2, LI Wenlong1, ZHANG Li1, ZHAO Zhonghai3(), ZHAO Handong1   

  1. 1. Heilongjiang Institute of Natural Resources Survey, Harbin, Heilongjiang 150036, China
    2. Institute of Geochemistry,Chinese Academy of Sciences, Guiyang , Guizhou 550081, China
    3. School of Mining, Liaoning Technical University, Fuxin, Liaoning 123000, China
  • Received:2020-03-23 Revised:2020-07-19 Online:2020-10-28 Published:2020-10-29
  • Contact: ZHAO Zhonghai

摘要:

大洋山斑岩型钼矿位于大兴安岭东北部呼中区,钼矿体主要产于石英二长斑岩体和上盘围岩中,产状受石英二长斑岩体控制。通过锆石LA-ICP-MS U-Pb定年,获得石英二长斑岩年龄为(119.83±0.87) Ma,可代表成矿年龄。岩石地球化学数据显示岩体偏铝、贫钛、富钾,具钾玄岩特征,为造山带岩石,岩浆熔体未与地幔相互作用;相对富集大离子亲石元素Rb和K,相对亏损高场强元素Nb、Ta、P、Ti和HREE,亲地幔元素亏损、轻稀土富集以及Eu中等亏损等特征显示岩浆源自陆壳。结合区域地质资料认为大洋山斑岩型钼矿形成于早白垩世晚期,成矿物质来源为地壳的重熔,与蒙古—鄂霍茨克洋的俯冲闭合相关,成矿环境为伸展构造背景。

关键词: 钼矿, 早白垩世, 地壳重熔, 大洋山, 大兴安岭, 蒙古—鄂霍茨克洋;

Abstract:

The Dayangshan molybdenum deposit is a newly discovered small deposit in the Huzhong area, northeast of Daxinganling. The ore is mainly hosted by the quartz-monzonite porphyry and hanging wall rock, and its occurrence is controlled by the quartz-monzonite porphyry. U-Pb dating of the quartz-monzonite porphyry using LA-ICP-MS yielded an age of (119.83±0.87) Ma, indicating that the mineralization in the Dayangshan molybdenum deposit occurred in the Early Cretaceous. The geochemical data of the quartz-monzonite porphyry show that the rock is relatively enriched in Al(Al2O3=15.04%-15.31%) and K(K2O/Na2O=1.15-1.21) and depleted in Ti(TiO2=0.36%-0.39%). These characteristics show that the quartz-monzonite porphyry is a potassic basaltic rock, which is normally formed in orogenic belt settings, and magmatic melts which produce these rocks do not interact with mantle. In addition, the rock is relatively enriched in LILEs (e.g., Rb and K), and depleted in HFSEs(e.g.,Nb, Ta, P, Ti and HREE), depleted in mantlephilic elements, enriched in LREE ((La/Sm)N=4.62-4.64), and with medium Eu value (δEu=0.46-0.48), suggesting that it was crystallized from a magma originated from continental crust. Based on the regional geological data, we argue that the source of ore-forming material was derived from the remelted crust related to the subduction and closure of the Mongolia-Okhotsk Ocean, and the mineralization occurred in the extensional tectonic setting. The study supplemented the data of regional metallogenic regularity and provided basis for regional metallogenic prediction.

Key words: molybdenum deposit, Early Cretaceous, remelting of the crust, Dayangshan, Daxinganling, Mongolia-Okhotsk Ocean

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