地学前缘 ›› 2021, Vol. 28 ›› Issue (2): 320-332.DOI: 10.13745/j.esf.sf.2020.6.30

• 非主题来稿选登 • 上一篇    下一篇

内蒙古撰山子金矿床流体包裹体特征与矿床成因

欧阳鑫1,2(), 章永梅1,3,4,*(), 顾雪祥1,4, 刘丽1, 王路智1, 高丽晔1   

  1. 1.中国地质大学(北京) 地球科学与资源学院, 北京 100083
    2.中国自然资源经济研究院, 北京 101149
    3.南京大学 内生金属矿床成矿机制研究国家重点实验室, 江苏 南京 210046
    4.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
  • 收稿日期:2019-02-24 修回日期:2019-06-12 出版日期:2021-03-25 发布日期:2021-04-03
  • 通讯作者: 章永梅
  • 作者简介:欧阳鑫(1994—),男,硕士,研究实习员,矿物学、岩石学、矿床学专业,主要从事矿床学、自然资源标准化研究。E-mail: ouyangxin@cugb.edu.cn
  • 基金资助:
    国家自然科学基金项目(41572062);中国地质调查局项目“东北内蒙古沿边及特殊地区地质矿产调查”(DD20160078);国家重点研发计划“深地资源勘查开采”课题(2018YFC0604003);原中国人民武警黄金部队科研项目(内蒙古敖汉地区典型金矿床成矿规律与找矿方向研究);中央高校基本科研业务费专项资金项目(2652017226)

Characteristics of fluid inclusions in and metallogensis of the Zhuanshanzi gold deposit in Inner Mongolia

OUYANG Xin1,2(), ZHANG Yongmei1,3,4,*(), GU Xuexiang1,4, LIU Li1, WANG Luzhi1, GAO Liye1   

  1. 1. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
    2. China Academy of Natural Resources and Economics, Beijing 101149, China
    3. State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210046, China
    4. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Beijing), Beijing 100083, China
  • Received:2019-02-24 Revised:2019-06-12 Online:2021-03-25 Published:2021-04-03
  • Contact: ZHANG Yongmei

摘要:

撰山子金矿床位于内蒙古台隆东段北缘华北克拉通与兴蒙造山带的结合部位。矿体赋存于下二叠统于家北沟组灰岩、中二叠世流纹岩和中三叠世花岗斑岩中,被晚三叠世闪长岩所截切。本文在查明矿床地质特征的基础上,对各成矿阶段热液矿物中的流体包裹体开展研究,查明了矿床成矿流体性质、演化特征及其与金成矿的关系。成矿阶段按从早到晚的顺序可分为石英-黄铁矿、石英-硫化物和石英-萤石-方解石阶段。流体包裹体岩相学和激光拉曼实验表明,热液矿物中原生包裹体可分为气液两相水型包裹体(Ⅰ型)、二氧化碳水三相型包裹体(Ⅱ型)、含子矿物三相型包裹体(Ⅲ型)、纯气相二氧化碳型包裹体(Ⅳ型)、纯气相水型包裹体(Ⅴ型)和纯液相水型包裹体(Ⅵ型)6种类型。成矿流体的温度和盐度从早阶段至晚阶段逐渐降低。成矿流体为中高温、中低和高盐度、中低密度的CO2-NaCl-H2O体系。主成矿阶段气液两相盐水和CO2-H2O三相包裹体限定的成矿压力范围分别为15.7~28.6、59.0~88.7 MPa,整体成矿深度范围在1.6~3.3 km之间。综合分析认为,撰山子金矿床在成矿过程中发生了流体不混溶(沸腾)作用,矿床的形成与中三叠世—晚三叠世华北板块和西伯利亚板块碰撞拼合引起的岩浆活动密切相关,是区内典型的中高温岩浆热液矿床。

关键词: 流体包裹体, 流体不混溶, 撰山子金矿床, 内蒙古

Abstract:

The Zhuanshanzi gold deposit is located on the northern margin of the eastern section of the Inner Mongolia Plateau, in the boundary area between the North China Craton and the Xingmeng orogenic belt. Its ore-bodies are hosted in the Lower Permian limestone (Yujiabeigou Formation), Middle Permian rhyolite and Middle Triassic granite-porphyry, intercalated by Late Triassic diorite. Based on the studies of fluid inclusions in hydrothermal minerals in various mineralization stages of the Zhuanshanzi gold deposit, we discuss in this paper the property and evolution of ore-forming fluids in the deposit. The ore-forming process can be divided into three metallogenic stages: quartz-pyrite, quartz-sulfide, and quartz-calcite-fluorite mineralization stages. Petrographic observation indicates fluid inclusions within the deposit can be divided into six types: biphasic vapor-aqueous, multiphasic CO2-H2O, daughter mineral-bearing multiphasic, monophasic CO2, monophasic vapor, and monophasic liquid inclusions. The temperature and salinity of the ore-forming fluids showed a decreasing trend from the first to the last metallogenic stage. The ore-forming fluid system is a CO2-NaCl-H2O system characterized by medium high temperature, medium low to high salinity and medium low density. In the main ore-forming stage, the ranges of hydrostatic pressures within the biphasic vapor-aqueous salt water system and triphasic CO2-H2O inclusions were 15.7-28.6 MPa and 59.0-88.7 MPa, respectively, and the ore-forming depth ranged between 1.6 and 3.3 km. It is considered that the immiscible (boiling) effect of the ore-forming fluid is the main mechanism of mineral precipitation, and the deposit is closely related to the magmatic activity caused by the collision between the North China and Siberian plates from the Middle to Late Triassic. The Zhuanshanzi gold deposit is a typical medium high temperature magmatic hydrothermal deposit in Inner Mongolia.

Key words: fluid inclusion, fluid immiscibility, Zhuanshanzi gold deposit, Inner Mongolia

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