地学前缘 ›› 2026, Vol. 33 ›› Issue (2): 76-87.DOI: 10.13745/j.esf.sf.2025.1.40

• 战略矿产前沿分析与勘查技术 • 上一篇    下一篇

基于太赫兹时域光谱的沉积岩含水性分析:以西秦岭造山型金矿三叠系赋矿围岩为例

滕卓尔1,2(), 李珊珊1,2,*(), 高子越1, 王洁1, 李康宁2, 侯朝宗1, 黄昊翀1, 郑志远1   

  1. 1.中国地质大学(北京) 地质过程与成矿预测全国重点实验室/深时数字地球前沿科学中心, 北京 100083
    2.甘肃省金矿资源勘查利用技术创新中心/甘肃省地质矿产勘查开发局第三地质矿产勘查院, 甘肃 兰州 730050
  • 收稿日期:2025-06-02 修回日期:2025-11-15 出版日期:2026-03-25 发布日期:2026-01-29
  • 通信作者: 李珊珊(1991—),女,高级实验师,博士生导师,主要从事矿床地球化学研究。E-mail: lishanshan199811@163.com
  • 作者简介:滕卓尔(2002—),男,博士,地质学专业。E-mail: zhuoerteng@qq.com
  • 基金资助:
    国家重点研发计划项目(2023YFE0125000);国家自然科学基金项目(42303067);甘肃省金矿资源勘查利用技术创新中心开放课题(JKZY-202505);北京科学技术协会青年人才托举工程项目(BYESS2024122);中央高校基本科研业务专项项目(2-9-2023-055);自然资源部新一轮找矿突破战略行动科技支撑项目(ZKKJ202410)

Analysis of water content in sedimentary rocks using terahertz time-domain spectroscopy: A case study from the Triassic ore-hosting rocks in the West Qinling orogenic gold deposit

TENG Zhuoer1,2(), LI Shanshan1,2,*(), GAO Ziyue1, WANG Jie1, LI Kangning2, HOU Chaozong1, HUANG Haochong1, ZHENG Zhiyuan1   

  1. 1. State Key Laboratory of Geological Processes and Mineral Resources/Frontiers Science Center for Deep-time Digital Earth, China University of Geosciences (Beijing), Beijing 100083, China
    2. Gold Mine Resource Exploration and Utilization Technology Innovation Center of Gansu Province/Third Institute of Geology and Mineral Exploration of Gansu Bureau of Geology and Mineral Resources, Lanzhou 730050, China
  • Received:2025-06-02 Revised:2025-11-15 Online:2026-03-25 Published:2026-01-29

摘要:

西秦岭造山型金矿成矿流体主要来源于区域地层中含水矿物在进变质作用过程中的脱水反应。尽管X射线衍射、傅里叶变换红外光谱和拉曼光谱等常规方法已被广泛应用于含水矿物的识别,但由于对氢元素敏感性较低、水相关信号干扰显著以及荧光效应的影响,这些方法在精确鉴定含水矿物类型和定量分析岩石水含量方面仍存在明显局限。太赫兹时域光谱(terahertz time-domain spectroscopy,THz-TDS)技术作为一种非破坏性光谱分析手段,对水分子集体振动模式及矿物晶格中水的赋存状态高度敏感,为岩石中含水矿物的有效识别与表征提供了新的技术途径。本研究以西秦岭造山带甘南地区三叠纪地层为研究对象,综合岩相学观察与太赫兹时域光谱分析,识别地层中的含水矿物并分析其含水特性,进而约束不同岩性的地层在进变质过程中发生脱水反应的潜力。结果表明,三叠纪地层中的绢云母、黑云母、绿泥石和褐铁矿等含水矿物表现出明显的太赫兹吸收特征,其中含分子水的褐铁矿呈现最显著的吸收特征峰。以绿泥石为主要含水矿物的砂岩显示出较高的太赫兹吸收系数与折射率,反映其具较高的含水量,表明该类岩石在进变质过程中能够通过脱水反应提供主要的成矿流体。本研究证实太赫兹时域光谱技术在沉积岩含水特性及含水矿物表征中具有良好的应用,为示踪造山型金矿成矿流体来源提供了新的技术方法。

关键词: 太赫兹时域光谱, 沉积岩, 岩石含水性, 含水矿物

Abstract:

The ore-forming fluids in the West Qinling orogenic gold deposit were predominantly derived from dehydration reactions of hydrous minerals during prograde metamorphism of regional strata. Although conventional methods such as X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy have been widely used for identifying hydrous minerals, they still exhibit significant limitations in precisely identifying hydrous mineral types and quantitatively analyzing rock water content due to their low sensitivity to hydrogen, significant interference from water-related signals, and fluorescence effects. As a non-destructive spectroscopic technique, terahertz time-domain spectroscopy (THz-TDS) is highly sensitive to the collective vibrational modes of water molecules and the occurrence states of water within mineral lattices, providing a novel technical approach for the effective identification and characterization of hydrous minerals in rocks. This study focuses on the Triassic strata in the Gannan region of the West Qinling orogenic belt. Integrating petrographic observations with THz-TDS analysis, we identified hydrous minerals and analyzed the state of water, thereby constraining the potential of different lithologies to undergo dehydration reactions during prograde metamorphism. The results indicate that hydrous minerals such as sericite, biotite, chlorite, and limonite in the Triassic strata exhibit distinct terahertz absorption features, with limonite (containing molecular water) showing the most prominent absorption peak. Sandstones rich in chlorite as the primary hydrous mineral display higher terahertz absorption coefficients and refractive indices, reflecting their higher water content. This suggests that such rocks can provide significant ore-forming fluids through dehydration reactions during prograde metamorphism. This study confirms the efficacy of THz-TDS in characterizing the aqueous properties and hydrous minerals of sedimentary rocks, offering a new technical method for tracing the source of ore-forming fluids in orogenic gold deposits.

Key words: terahertz time-domain spectroscopy, sedimentary rocks, water-bearing capacity of rocks, hydrous minerals

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