稀土元素在岩浆和水热系统的实验岩石学和地球化学研究进展

Research advances in experimental petrology and geochemistry of rare earth elements in magmatic and hydrothermal systems

稀土元素对绿色科技的发展具有至关重要的作用,随着世界范围内新兴技术的发展进程对稀土的需求日益提高,稀土矿床成矿机理的研究已经成为目前国际地学的研究热点。稀土元素分配行为的高温高压实验能够为研究稀土在岩浆和水热系统中的迁移、分异和沉淀机制提供有效制约,为了解稀土元素地球化学行为和稀土成矿作用提供重要的理论基础。本文总结了近年来关于稀土元素在岩浆-热液体系中分配行为的高温高压实验研究进展,其中包括部分熔融作用稀土的分配行为,液态不混熔过程中稀土在共轭熔体相之间的分配系数,分离结晶作用过程中稀土在结晶矿物相与残余熔体相之间的分配系数,岩浆演化后期稀土在熔体和分异流体相之间的分配行为,以及稀土在热液流体中的迁移、分异和沉淀机制的相关研究。基于目前的实验研究结果,本文提出了稀土实验地球化学研究中依旧存在的一些问题:部分熔融作用对于成矿物质组成的影响,碳酸盐熔体和硅酸盐熔体液态不混熔对于碳酸岩稀土成矿作用的影响,岩浆晚期演化的热液流体对于稀土成矿作用的影响,稀土元素在液态不混熔、分离结晶和热液交代过程中的分异和富集机制等,并对未来需要继续完善和拓展的方向提出了展望。

With the development of new technologies and the increasing demands for rare earth elements(REEs)around the world,the metallogenic mechanism of rare earth deposits has become an international research hotspot.High-temperature and high-pressure experiments on the distribution behavior of rare earth elements can provide effective constraints for studying the migration,differentiation,and deposition mechanisms of rare earth elements in the magmatic and hydrothermal systems.The experiment results provide an important theoretical basis for the understanding of geochemical behavior of rare earth elements and the mineralization processes in the REE deposits.In this paper,we summarize the recent high-temperature and high-pressure experimental knowledge advances in the distribution behavior of rare earth elements in the magmatic and hydrothermal systems,including partial melting,liquid-liquid immiscibility,fractional crystallization,fluid-melt partitioning,as well as the migration,differentiation and precipitation mechanism of rare earth elements in the hydrothermal fluids.Finally,future work that enhances our understanding of rare earth elements migration and deposition mechanisms in magmatic and hydrothermal systems are briefly proposed.