流体包裹体LA-ICP-MS成分分析对碳酸岩型稀土矿床流体成分和演化过程的制约:以河南太平镇稀土矿床为例

碳酸岩型稀土矿床的成矿流体比较复杂，含有大量硫酸根、碳酸根、磷酸根以及氯离子，传统的分析手段无法准确获得成矿流体的盐度以及元素含量等信息，制约了对成矿流体演化过程以及成矿机制等问题的认识。近年来，单个流体包裹体LA-ICP-MS成分分析技术发展迅速，已经实现对各种阳离子以及S等阴离子的定量分析，是研究成矿流体成分最重要的手段之一。河南省太平镇稀土矿床记录了稀土矿化完整的信息，并且不同成矿阶段石英中均发育流体包裹体，是探索碳酸岩型稀土矿床成矿流体成分与演化过程的理想对象。本申请拟以太平镇稀土矿床为研究对象，在显微测温和激光拉曼光谱分析的基础上，对各阶段流体包裹体开展系统的LA-ICP-MS成分分析，查明各阶段流体在温度、压力和成分上的变化规律，建立成矿流体演化模型，并揭示控制稀土元素迁移与沉淀的机制。本项目有望在碳酸岩型稀土矿床成矿流体方面取得创新性认识，进一步完善碳酸岩型稀土矿床成矿理论。

The ore-forming fluids in carbonatite-related REE deposits contain a variety of species including sulfate, carbonate, phosphate and chloride ions. Therefore, conventional methods of fluid inclusion including microthermometry, Raman spectroscopy, and bulk crush and leach quantification are unable to obtain the accurate salinity and composition of ore-forming fluid, restricting the understanding of fluid evolution and mineralization in the deposit. Recent development of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) allows in situ analyzing the composition of sulfate-bearing fluid inclusions, and thus can be used to investigate the nature of ore-forming fluid in carbonatite-related REE deposits. Taipingzhen REE deposit in the Henan province is a typical carbonatite-related REE deposit. It is well preserved and contains abundant fluid inclusions in quartz from all paragenetic stages, and thus provides an excellent opportunity for studying the nature and evolution of ore-forming fluid in the carbonatite-related REE deposit. In this project, based on microthermometric and Raman spectroscopic work, we will conduct detailed LA-ICP-MS analysis of fluid inclusions in the Taipingzhen deposit, in order to characterize the chemical composition of the fluids in each stage and reconstruct the fluid evolution process, and further reveal the transportation and precipitation of REEs. This project may obtain an innovative understanding of ore-forming fluids and mineralization process in the carbonatite-related REE deposits.