西藏甲玛矿床磁黄铁矿微量元素特征及其与金富集沉淀的耦合机制
作者:
作者单位:

作者简介:

通讯作者:

中图分类号:

P618.51

基金项目:

国家重点研发计划-深地专项(2018YFC0604101)、中国地质科学院矿产资源研究所基本科研业务费(KJ2102、KK2017)、西藏自治区科技计划项目(XZ201901-GB-24)、国家自然科学基金项目(419002097)和中国地质调查局项目(DD20190167)联合资助。


Geochemistry of pyrrhotite in the Jiama deposit, Tibet and its relationship with gold enrichment and precipitation
Author:
Affiliation:

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
  • |
  • 文章评论
    摘要:

    研究目的】甲玛矿床是西藏冈底斯成矿带最重要的斑岩成矿系统之一,具有斑岩、矽卡岩、角岩、脉状金矿四位一体矿体结构,形成了丰富的矿物种类和多样的金属矿化。其中,磁黄铁矿作为重要的金属矿物之一,其矿物地球化学特征以及与金矿化的耦合关系一直不明确。【研究方法】此次,以甲玛斑岩成矿系统外围和远端的不同产状的磁黄铁矿为研究对象,基于详细的野外地质调查和镜下鉴定,通过激光剥蚀电感耦合等离子质谱分析方法(LAICP-MS)对不同产状的磁黄铁矿开展测点分析和扫描分析,详细揭示其地球化学特征。【研究结果】结果显示,甲玛矿床磁黄铁矿主要富集Co、Ni、Cu、Zn、Ge、Se,弱富集Pb、Bi、Sb、Te、Ag、As,而Mo、Cd、In、Sn、Ba、W、Au、Tl、Th、U等元素含量较低。其中,矽卡岩中的磁黄铁矿具有较高的Co/Ni比值,能有效揭示其岩浆热液成因,而角岩中磁黄铁矿可能继承了一定的沉积特征。【结论】甲玛矿区磁黄铁矿的Cu、Zn、Pb含量变化特征与矿床空间矿化规律一致。矽卡岩中的块状磁黄铁矿与金矿化关系密切,金主要呈他形、不规则的独立金矿物产于磁黄铁矿的孔隙和粒间。同时,金的富集和沉淀可能与富铋的熔体有关。
    创新点:磁黄铁矿是甲玛超大型斑岩成矿系统中典型的金属矿物之一,其微区原位分析清晰揭示其微量元素地球化学特征和矿物成因,同时,证实矽卡岩中磁黄铁矿的高品位金与成矿流体中的富铋熔体有关。

    Abstract:

    This paper is the result of mineral exploration engineering.
    [Objective]As one of the most important porphyry metallogenic systems in Gangdese metallogenic belt in Tibet, Jiama has a four in one orebody structure of porphyry, skarn, hornfels, and vein gold ore-body, forming riched minerals and diverse metal mineralization. Pyrrhotite is one of the important metal minerals, and its mineral geochemistry and relationship with gold mineralization are still obscure.
    [Methods]The mineralogy and geochemistry of pyrrhotite in different occurrences of the Jiama porphyry system are the main objects for this paper according to detailed field geological survey, petrography, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis.
    [Results]The results show that pyrrhotite is obviously enriched in Co, Ni, Cu, Zn, Ge, and Se, and weakly enriched in Pb, Bi, Sb, Te, Ag, and As, and low content of Mo, Cd, In, Sn, Ba, W, Au, Tl, Th, U, relatively. Moreover, the pyrrhotite from skarn has a high ratio of Co/Ni, represent the its magmatic-hydrothermal genesis, while the pyrrhotite hosted in hornfels shows sedimentary characteristics.
    [Conclusions]The variation of contents of Cu, Zn, and Pb in pyrrhotite are related to the spatial mineralization in the Jiama deposit. The massive pyrrhotite in skarn is closely related to gold mineralization and the gold is mainly anhedral or irregular free gold occurring in the cavity and boundary of pyrrhotite grains. The enrichment and precipitation of gold could be related to bismuth-rich melts in the ore-fluids.
    Highlights: Pyrrhotite is one of the important metal mineral in the Jiama deposit. The LA-ICP-MS analysis of pyrrhotite shows its geochemistry and genesis. The high-grade Au in pyrrhotite hosted in skarn could be related to the bismuth-rich melts in the orerelated fluids.

    参考文献
    相似文献
    引证文献
引用本文

杨征坤,杨阳,张忠坤,林彬,赫健,张泽斌,高福太,唐晓倩,唐攀,祁婧,李怡萱. 西藏甲玛矿床磁黄铁矿微量元素特征及其与金富集沉淀的耦合机制[J]. 中国地质, 2022, 49(4): 1198-1213.
YANG Zhengkun, YANG Yang, ZHANG Zhongkun, LIN Bin, HE Jian, ZHANG Zebin, GAO Futai, TANG Xiaoqian, TANG Pan, QI Jing, LI Yixuan. Geochemistry of pyrrhotite in the Jiama deposit, Tibet and its relationship with gold enrichment and precipitation[J]. Geology in China, 2022, 49(4): 1198-1213(in Chinese with English abstract).

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2020-06-21
  • 最后修改日期:2020-10-10
  • 录用日期:
  • 在线发布日期: 2022-09-09
  • 出版日期: 2022-08-20
温馨提示:建议您使用Chrome、火狐、IE最新版本 ,当您的浏览器版本过低,可能会影响部分功能正常使用。
关闭