花岗岩风化过程中稀土元素迁移富集机制研究进展

Recent Advances in Migration and Enrichment of Rare Earth Elements During Chemical Weathering of Granite

风化壳淋积型稀土矿床的矿化与化学风化作用密切相关,华南风化壳淋积型稀土矿床是一种重要的稀土资源类型,具有储量大、分布范围广和富含重稀土等特点。近年来,风化过程中稀土元素迁移富集机制和风化壳淋积型稀土矿床成矿机理问题被越来越多的人关注,已成为地球科学研究的热点问题之一。通过系统总结前人工作,归纳出风化壳淋积型稀土矿床成矿特点及过程、花岗岩风化壳的结构特征、稀土元素在风化剖面中的分布、迁移与赋存方式、稀土元素在风化剖面中迁移和富集的主要影响因素以及Eu和Ce元素异常特征,旨在进一步理解表生风化过程中稀土元素的行为,并对当前化学风化过程中稀土研究的一些问题进行了展望。非传统稳定同位素示踪化学风化新颖有效且优势明显,目前已成功建立Ce和Nd等稀土稳定同位素分析测试方法,未来研究工作应将稀土元素和同位素手段有效结合,有望在示踪化学风化过程、揭示稀土矿化以及研究环境演化等方面取得重要认识。

The mineralization process of elution-deposited Rare Earth Element(REE)deposits is closely related to chemical weathering.Elution-deposited REE deposits in South China are an extremely important type of rare resource,with large reserves,a wide distribution,and a high content of Heavy REEs(HREE).In recent years,the migration and enrichment mechanism of earth elements during the chemical weathering process and the ore-forming mechanism of elution-deposited REE deposits has garnered great research interest.This subject has become one of the central issues in geoscience research.Multiple aspects,such as the metallogenic characteristics and processes of elution-deposited REE deposits,structural characteristics of granite weathering crust,distribution characteristics of REEs,occurrence and migration modes of REEs,main factors affecting the migration and enrichment of REEs,and the characteristics of Eu and Ce anomalies are systematically summarized in this paper.The purpose of this study is to comprehensively summarize knowledge centered on the behavior of REEs in the process of supergene weathering,to provide novel directions for future research.Nontraditional stable isotope tracing of chemical weathering is novel and effective;specifically,stable isotope analysis methods for Ce and Nd have been successfully established.Therefore,future research should explore earth elements through the lens of isotopic methods,as this approach could provide important insights for tracing chemical weathering,revealing the mineralization process of REE deposits,and studying environmental evolution.