地学前缘 ›› 2023, Vol. 30 ›› Issue (3): 399-424.DOI: 10.13745/j.esf.sf.2022.10.46

• 非主题来稿选登 • 上一篇    下一篇

镁同位素体系在重要地质过程中的应用

刘嘉文1,2(), 田世洪1,2,3,*(), 王玲1,*()   

  1. 1.东华理工大学 核资源与环境国家重点实验室, 江西 南昌 330013
    2.东华理工大学 地球科学学院, 江西 南昌 330013
    3.自然资源部深地科学与探测技术实验室, 北京 100094
  • 收稿日期:2022-04-27 修回日期:2022-10-30 出版日期:2023-05-25 发布日期:2023-04-27
  • 通讯作者: *田世洪(1973—),男,研究员,博士生导师,主要从事同位素地球化学与矿床学研究工作。E-mail: s.h.tian@163.com;王 玲(1989—),女,助理研究员,主要从事同位素地球化学与变质岩地球化学研究工作。E-mail: wangling@ecut.edu.cn
  • 作者简介:刘嘉文(1996—),女,硕士研究生,地质工程专业,主要从事同位素地球化学与矿床学研究。E-mail: jiawenl96@126.com
  • 基金资助:
    国家重点研发计划“战略性矿产资源开发利用”专项“我国西部伟晶岩型锂等稀有金属成矿规律与勘查技术项目”(2021YFC2901900);“北喜马拉雅锂等稀有金属找矿预测与勘查示范课题”(2021YFC2901903);国家自然科学基金项目(42002095);中国铀业有限公司-东华理工大学核资源与环境国家重点实验室联合创新基金项目(2022NRE-LH-05);自然资源部深地科学与探测技术实验室开放课题(SinoProbe Lab 202217);江西省“双千计划”创新领军人才长期项目(2020101003);东华理工大学核资源与环境国家重点实验室自主基金项目(2020Z08);东华理工大学实践教学类项目(DHSY-202217);江西省自然科学基金重点项目(20224ACB203011);东华理工大学高层次人才引进配套经费资助项目(1410000874)

Application of magnesium stable isotopes for studying important geological processes—a review

LIU Jiawen1,2(), TIAN Shihong1,2,3,*(), WANG Ling1,*()   

  1. 1. State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China
    2. School of Earth Sciences, East China University of Technology, Nanchang 330013, China
    3. SinoProbe Laboratory of Chinese Academy of Geological Sciences, Ministry of Natural Resources, Beijing 100094, China
  • Received:2022-04-27 Revised:2022-10-30 Online:2023-05-25 Published:2023-04-27

摘要:

Mg作为主要的造岩元素,其丰度在地球上排第四位(仅次于O、Fe和Si)。Mg在自然界中存在3种稳定同位素,分别为24Mg、25Mg和26Mg,其中26Mg和24Mg之间具有较大的质量差(8.33%),在各类地质过程中显示出不同程度的分馏,使之成为研究不同地质演化过程的有力指标和良好示踪剂。近年来,随着分析方法的改进和同位素质谱技术的发展,Mg同位素的应用得到大跨步的发展。前人从不同角度对Mg同位素研究进展进行了综述,本文在简要介绍Mg同位素标准物质和分析方法的基础上,详细阐述了Mg同位素在地质学4个领域方面的应用,包括:(1)Mg同位素在矿床成因方面的应用,能够有效示踪成矿过程、成矿物质来源等;(2)Mg同位素在煌斑岩成因方面的应用,可有效示踪源区物质组成;(3)Mg同位素在地质温度计方面的应用,概述了较为常见的四种矿物对Mg同位素地质温度计并分析了其适用性;(4)含石榴石的变质作用、转熔反应和岩浆作用中的Mg同位素分馏及其指示意义。总之,本文通过对Mg同位素在上述重要地质过程中研究成果的系统总结,旨在加深对Mg同位素体系的深入理解,进一步显示Mg同位素体系具有非常广阔的应用前景。

关键词: Mg同位素, 分析方法, 矿床成因, 煌斑岩成因, 地质温度计, 变质岩浆过程

Abstract:

Magnesium (Mg) is the fourth most abundant major rock-forming element on Earth (after O, Fe and Si). It has three naturally occurring stable isotopes, 24Mg, 25Mg and 26Mg, among them the relative atomic mass difference between 26Mg and 24Mg is up to 8.33%. Such a large relative atomic mass difference can result in variable degrees of Mg isotope fractionation in different geological processes, thus making Mg stable isotopes effective tracers for studying various geological evolution processes. In recent years, improvements of isotope analytical methods and the development of isotope-ratio mass spectrometry have greatly expanded the use of Mg stable isotopes in geological research, and the related publications have been comprehensively reviewed. Here, following a brief introduction to the reference materials and analytical methods for Mg isotope analysis, this paper discusses in detail the application of Mg isotope in four geological research fields, including applications 1) in ore genesis studies as effective tracers for probing mineralization processes and source of ore-forming materials; 2) in lamprophyre genesis studies for compositional analysis of source materials; 3) in geothermometer research, where four common mineral-pair Mg isotope geothermometers are reviewed and their applicability analyzed; and 4) in the study of Mg isotopic fractionation during metamorphic evolution, peritectic reaction and magmatic processes involving garnet-bearing rocks, and its implications. This systematic review is aimed to deepen the understanding of Mg stable isotopes and further demonstrate their broad application prospects.

Key words: Mg isotopes, analytical method, ore genesis, lamprophyre genesis, geological geothermometer, metamorphic magmatic process

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