铁同位素及其在古海洋环境演化过程中的应用  

Iron Isotopes and Their Application in the Evolution of Ancient Oceans

作　　者：杨曦[1] 王义东[1] 王中良 YANG Xi;WANG Yidong;WANG Zhongliang(Tianjin Key Laboratory of Water Resources and Environment,Tianjin Normal University,Tianjin 300387,China;School of Environmental and Municipal Engineering,Tianjin Chengjian University,Tianjin 300384,China)

机构地区：[1]天津师范大学天津市水资源与水环境重点实验室,天津300387 [2]天津城建大学环境与市政工程学院,天津300384

出　　处：《地球与环境》2025年第1期143-152,共10页Earth and Environment

基　　金：国家自然科学基金青年科学基金项目(42303014)。

摘　　要：铁是具有多价态特性的氧化还原敏感元素,其形态和同位素经常被作为环境标识,尤其是对现代和古海洋有重要的环境指示意义。本文通过总结铁在现代和古海洋环境中的同位素组成及分馏机制、评述早期含铁矿物的成因,来支持太古代早期就出现了厌氧氧化作用的观点。厌氧氧化作用将海洋中部分溶解铁氧化,这导致了溶解态铁富集轻铁同位素并间接造成了铁建造的形成。研究古海洋含铁矿物的成因极其困难,这是由于现代环境极难还原古海洋环境的化学物理条件。同位素技术的发展实现了低含量铁的同位素测定,铁同位素及其分馏可以示踪古海洋中铁元素的行为特征并指示当时的海洋环境。因此,现代研究需要结合实验室模拟和现代类太古代环境来解决古海洋中铁同位素分馏机制,并结合其他元素的多同位素技术手段探讨古海洋中化学成分和含铁矿物的成因,这对矿产资源的探寻和生命起源的探索具有重要的意义。Iron is a redox-sensitive element with multiple valence states,and its forms and isotopes are often used as environmental markers,particularly significant in indicating conditions in both modern and ancient marine environments.This paper summarizes the isotopic composition and fractionation mechanisms of iron in modern and ancient marine environments and reviews the genesis of early iron-bearing minerals to support the view that anaerobic oxidation processes existed in the early Archean.Anaerobic oxidation processes led to the oxidation of part of the dissolved iron in the ocean,which resulted in the enrichment of light iron isotopes in dissolved iron and indirectly contributed to the formation of banded iron formations(BIFs).Studying the genesis of iron-bearing minerals in ancient oceans is extremely challenging due to the difficulty in reproducing the chemical and physical conditions of ancient marine environments in modern settings.The advancement of isotopic techniques has enabled the measurement of iron isotopes in low concentrations,allowing iron isotopes and their fractionation to trace the behavior of iron in ancient oceans and to indicate the marine environment at that time.Therefore,modern research needs to combine laboratory simulations and modern Archean-like environments to resolve the mechanisms of iron isotope fractionation in ancient oceans.Additionally,the use of multi-isotope techniques of other elements to explore the chemical composition and genesis of ironbearing minerals in ancient oceans is of great significance for the exploration of mineral resources and the study of the life origins.

关 键 词：铁同位素 铁同位素分馏 铁形态 氧化还原环境标识 

分 类 号：X142[环境科学与工程—环境科学]