摘要
矿床的形成受制于多种复杂的地质作用,包括全球尺度的板块构造运动、岩浆活动、变质沉积改造等过程,并普遍伴随热液活动、流体迁移、水-岩相互作用、元素分异及同位素分馏等一系列局部区域地质和地球化学过程.在过去的矿床学研究中,地球化学方法主要围绕在主、微量元素和传统的稳定同位素等手段,解决了很多矿床成因问题.但仍存在不少的多解和难解问题,比如许多矿床在矿化类型、蚀变分带与金属矿物组合方面具有诸多相似之处,常规地球化学指标难以区分.随着测试精度的提高和自然储库组成的完善,Li同位素近些年来已成为新兴的稳定同位素体系.Li同位素在自然界过程中高达80‰的同位素分馏使其具有更好的辨识能力,同时兼有直接和间接指示作用,有潜力成为研究各种复杂成矿过程的良好示踪剂.本文总结了近年来有关矿床学中Li同位素的研究和应用进展,以俯冲带成矿为主,阐述了斑岩型-热液矿床、伟晶岩型矿床和沉积矿床等类型矿床的Li同位素地球化学特征,并探究新的Li同位素方法在矿床中的应用前景.基于Li同位素体系在各类矿床的应用实例,我们认为Li同位素体系将为矿床学研究提供更多的指示信息和依据.
The formation of ore deposits is subject to varieties of complex geological processes, including plate tectonics,magmatic activities, metamorphic sedimentary transformations and other processes on global scale, and is generally accompanied by a series of geological and geochemical processes such as hydrothermal activities, fluid migration, fluid-rock interaction,elemental differentiation and isotopic fractionation. Over the past decades, studies of geochemical methods have focused on major,trace elements and traditional stable isotopes, that have addressed the genesis of ore deposits. However, there are still some difficulties and multi solutions. For instance, portions of ore deposits in the mineralization, alteration zoning, and metal mineral assemblage have many similarities, so the conventional geochemical indicators are difficult to be distinguished. With the improvement of analysis and the integrity of natural reservoir composition, Li isotope has become a new stable isotope system in recent years. The Li isotopic fractionation of up to 80‰ in the natural process enhances the identification ability of Li isotope, as well as in direct or indirect indicator function. Thus, Li isotopic systematics has the potential to be a good tracer to study various complex metallogenic processes. Here, this paper summarizes the studies and applications of Li isotopes on ore deposit in recent years, mainly in subduction zone mineralization, the geochemical behavior and characteristics of Li isotopes in porphyryhydrothermal deposits, pegmatite deposits and sedimentary deposits, then it explores an application prospect of new Li isotopic method for ore deposits. Based on the applications of Li isotopic system in various ore deposits, it proposes that Li isotopic system will provide more indicative information for ore deposit study in the future.
作者
陆一敢
肖益林
王洋洋
万红琼
李东永
仝凤台
余成龙
Lu Yigan;Xiao Yilin;Wang Yangyang;Wan Hongqiong;Li Dongyong;Tong Fengtai;Yu Chenglong(CAS Key Laboratory of Crust-Mantle Materials and Environments,School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China;CAS Center for Excellence in Comparative Planetology,Hefei 230026,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2021年第12期4346-4365,共20页
Earth Science
基金
国家自然科学基金项目(Nos.41673031,42073003,41729001)资助。
关键词
Li同位素
同位素分馏
俯冲带
成矿流体
斑岩铜矿
地球化学
Li isotopes
isotopic fractionation
subduction zone
ore-forming fluid
porphyry copper deposit
geochemistry
