中国科学院地球化学研究所尹润生教授团队最新的研究揭示了华南含汞热液系统独特的汞同位素特征及其地质环境意义。相关论文于2024年12月11日发表在《地质学》杂志上。

据介绍，巨型华南低温成矿带（LTMD）中有许多低温热液系统（如右江的金-砷-锑-汞矿床，湘中的锑-金矿床和湘黔的汞矿床），提供了全球约80%的汞金属产量。

研究人员对湘黔汞矿床的汞同位素组成进行了研究，并对右江金-砷-锑-汞矿床和湘中锑-金矿的现有资料进行了重新评价。来自8个湘黔汞矿床中的朱砂样品的Δ¹⁹⁹Hg值均为负至近零，表明其汞有两个来源：（1）软流圈地幔（Δ¹⁹⁹Hg值接近于零）；（2）前寒武纪基底（Δ¹⁹⁹Hg值为负）。右江金-砷-锑-汞矿床和湘中锑-金矿床也存在这种混合作用。

结合这些矿床的年龄推断，加里东期、印支期和燕山期构造-热事件期间的板块俯冲和碰撞，引发了华南克拉通内部岩石圈伸展、软流圈上涌和基底再活化，形成了岩浆热液流体和富金属热液，最终形成了LTMD的低温热液系统。研究结果强调，中国低温热液含汞矿床的δ²⁰²Hg-Δ¹⁹⁹Hg模式与欧洲和南北美洲的矿床具有明显的差异，这意味着可以利用汞同位素追踪全球市场的汞强度。

附：英文原文

Title: Unique mercury isotopic signature of mercury-bearing hydrothermal systems in South China and its geological and environmental implications

Author: Bizheng Yang, Chenchen Yang, Zhendong Tian, Changzhou Deng, Bernd Lehmann, Runsheng Yin

Issue&Volume: 2024-12-11

Abstract: The giant South China low-temperature metallogenic domain (LTMD) hosts many low-temperature hydrothermal systems (e.g., the Youjiang Au-As-Sb-Hg ore deposits, Xiangzhong Sb-Au ore deposits, and Xiangqian Hg ore deposits), which provide ～80% of the global Hg metal production. Here, we study the Hg isotopic composition of the Xiangqian Hg deposits and re-evaluate available data on the Youjiang Au-As-Sb-Hg deposits and Xiangzhong Sb-Au deposits. Cinnabar samples from eight Xiangqian Hg deposits display negative to near-zero Δ¹⁹⁹Hg values, suggesting that their Hg is from two sources: (1) the asthenospheric mantle with near-zero Δ¹⁹⁹Hg values, and (2) the Precambrian basement with negative Δ¹⁹⁹Hg values. Such mixing is also observed in the Youjiang Au-As-Sb-Hg deposits and Xiangzhong Sb-Au deposits. Combining the ages of these deposits, we infer that plate subduction and collision during Caledonian, Indosinian, and Yanshanian tectonic-thermal events triggered lithospheric extension, asthenospheric upwelling, and basement remobilization within the South China craton, leading to the generation of magmatic-hydrothermal fluids and metal-rich crustal fluids to form low-temperature hydrothermal systems in the LTMD. This work demonstrates that Hg-bearing low-temperature hydrothermal deposits in China have distinct δ²⁰²Hg-Δ¹⁹⁹Hg patterns from those in Europe and North and South America, implying that Hg isotopes can be used for tracing the sources of Hg in the global market.

DOI: 10.1130/G52619.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52619.1/650589/Unique-mercury-isotopic-signature-of-mercuryredirectedFrom=fulltext