Groundwater samples were collected from Shanmughanadhi in Dindigul district of Tamilnadu, India, to determine the concentration and fractionation of REEs during chemical weathering. Groundwater samples collected from aquifers hosted in weathered and fractured crystalline formations were analyzed by ICP-MS for Rare earth elements (REEs) after filtering by 0.45 μm membrane filters. ΣREEs in Charnockite accounts 8.49 × 10⁻⁴mgL⁻¹ and 1.08 × 10⁻³mgL⁻¹ in hornblende biotite gneiss signifying higher REEs in Gneiss than Charnockite, due to higher flushing rates in gneiss and relatively shorter water residence time in Charnockite aquifer. Higher LREEs were observed upstream in the study area, followed by enrichment of MREEs and HREEs in midstream and discharge areas, respectively. Irrespective of lithology, the groundwater samples mostly exhibited a positive europium anomaly, which might be due to higher dissolution and mobilization of europium from plagioclase group minerals through rock-water interaction. The plagioclase feldspar, orthopyroxene, and alkali feldspars mineral weathering rates were 124, 17.5, and 20.0 mol/hectare/year. The rare earth minerals enriched in the host rocks provided the referenced material for the REE enrichment in the groundwater. Variations in pH and redox conditions in groundwater environments have influenced the enrichment of REE aided by continuous aquifer residence time, chemical weathering, and groundwater flow path.

从印度泰米尔纳德邦Dindigul区的Shanmughanadhi收集了地下水样品，以确定化学风化过程中REE的浓度和分级。经0.45μm膜滤器过滤后，通过ICP-MS分析从风化破裂晶体层中含水层中收集的地下水样品中的稀土元素（REE）。Charnockite帐户中的ΣREE为8.49×10 ^-4 mgL ^-1和1.08×10 ^-3 mgL ^-1在角闪石黑云母片麻岩中，片麻岩中的稀土元素含量高于Charnockite，这是由于片麻岩中较高的冲刷速率和在Charnockite含水层中的水停留时间相对较短。在研究区上游观察到较高的LREE，随后在中游区和排放区分别富集了MREE和HREE。不论岩性如何，地下水样品大多表现出正euro异常，这可能是由于rock通过岩水相互作用从斜长石族矿物中溶解和迁移的euro含量更高。斜长石，邻苯二茂铁和碱金属长石的矿物风化速率分别为124、17.5和20.0 mol /公顷/年。富集在基质岩石中的稀土矿物为地下水中稀土元素的富集提供了参考资料。