Rare earth element mineralizations in the Palabora Carbonatite Complex

碳酸盐岩是稀土元素最重要的来源，在许多现代技术，特别是绿色技术中起着关键作用。因此，详细了解碳酸盐岩相关稀土矿床的形成位置和形成方式对这些重要资源的矿产勘探和未来开发至关重要。该项目将系统地调查迄今为止几乎没有记录的南非Palabora碳酸盐岩复合体（PCC）的REE矿化。PCC是一个非常适合的研究对象，因为它的矿物学变量和多阶段的REE矿物组合，以及系统地研究垂直距离约1500米的REE矿物变化的独特可能性，可以回答与碳酸盐岩相关的REE矿化的重要问题。将进行详细的岩石学、EMPA和LA-ICP-MS工作，以跟踪各种稀土矿物组合的结构和成分演化的空间变化。全岩分析，包括高质量的稀土元素数据，将通过XRF和ICP-MS进行，这将允许通过复杂识别化学变化。流体包裹体的表征（显微测温、拉曼光谱、气相色谱- irms）将与形成岩石的矿物的稳定同位素数据相结合，这将允许破译参与各种稀土矿化形成和再活化的各种流体来源。研究结果将进一步加深我们对碳酸盐岩侵位、岩浆-热液演化及其相关稀土矿化的认识，包括物理化学参数（如P、T、pH、fO2、aH2O、aCO2、aHF、aHCl）的潜在变化和流体来源的变化，这些变化可能直接影响稀土矿物组合类型。

Carbonatites represent the most important source for REE, which play a key role for many modern, especially green technologies. Therefore, the detailed understanding of where and how carbonatite-related REE deposits form is critical to mineral exploration and future development of these important resources. This project will systematically investigate the so-far barely documented REE mineralization of the Palabora Carbonatite Complex (PCC) in South Africa. The PCC is a perfectly suited research object to answer important questions concerning carbonatite-related REE mineralizations because of its mineralogicaly variable and multi-stage REE-mineral assemblages and the unique possibility to systematically investigate mineralogical changes with respect to REE-minerals over a vertical distance of about 1500 m. Detailed petrography, EMPA and LA-ICP-MS work will be performed to track spatial variations in the textural and compositional evolution of the various REE-mineral assemblages. Whole-rock analyses, including high quality REE data, will be carried out by XRF and ICP-MS, which will allow for identifying chemical variations through the complex. Characterization of fluid inclusions (microthermometry, Raman spectroscopy, gas chromatography-IRMS) will be combined with stable isotope data for rock-forming minerals, which will allow for deciphering the various fluid sources involved in the formation and remobilization of the various REE mineralizations. The results of this study will enhance our knowledge concerning the emplacement and the magmatic to hydrothermal evolution of carbonatitic systems and their associated REE mineralization with depth, including potential changes in physico-chemical parameters (e.g., P, T, pH, fO2, aH2O, aCO2, aHF, aHCl) and changing fluid sources, which may have direct consequences on the type of REE-mineral assemblage.