Acid mine drainage (AMD) generated from coal and sulfide mining has attracted much interest due to the high concentrations of rare earth elements (REE) observed. However, the origin of REE in AMD and particularly the mechanism of enrichment in medium REE remain uncertain. The combined study of Sr and Nd isotopes can be used to trace the processes that control the mobility and fractionation of REE in aquatic systems such as AMD. This work reports for the first time worldwide isotopic data of Sr and Nd in AMDs from sulfide mining (Iberian Pyrite Belt, SW Spain) and compare with those in host rocks. Additionally, leaching experiments have been carried out to simulate the water–rock interactions found in these acidic systems. The results obtained strongly suggest that the origin of REE in AMDs from metal mining may be related to the preferential dissolution of shales and felsic rocks. The suitability of Sr and Nd isotopic signatures to trace the REE source in AMD-affected systems has been proven, it provides a new environmental and geochemical prospecting tool which could be useful in different geological water–rock interaction systems.

中文翻译：

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锶和钕同位素追踪酸性矿山排水中稀土元素的来源

由于观察到高浓度的稀土元素 (REE)，煤炭和硫化物开采产生的酸性矿山排水 (AMD) 引起了人们的广泛关注。然而，AMD 中 REE 的来源，特别是介质中 REE 的富集机制仍不确定。 Sr 和 Nd 同位素的综合研究可用于追踪控制 REE 在水生系统（如 AMD）中的移动性和分馏的过程。这项工作首次报告了来自硫化物开采（西班牙西南部伊比利亚黄铁矿带）的 AMD 中 Sr 和 Nd 的全球同位素数据，并与母岩中的数据进行了比较。此外，还进行了浸出实验来模拟这些酸性系统中发现的水-岩石相互作用。获得的结果有力地表明，金属采矿产生的AMD中稀土元素的来源可能与页岩和长英质岩石的优先溶解有关。 Sr和Nd同位素特征在受AMD影响的系统中追踪稀土元素来源的适用性已得到证明，它提供了一种新的环境和地球化学勘探工具，可用于不同的地质水岩相互作用系统。