皖北任楼煤矿深层地下水稀土元素地球化学特征

为深入理解深层地下水稀土元素特征及水岩相互作用机制，对皖北任楼煤矿深部3个含水层（四含、煤系和太灰水）的稀土元素组成进行了测试，结果表明:任楼煤矿3个含水层均以轻稀土亏损、重稀土富集为特征，且均具有明显的Eu正异常以及普遍的负Ce异常，但三者在稀土分异、Eu和Ce异常程度上存在区别。其中，Ce异常主要与氧化还原程度有关，正Eu异常除与测试中BaO的干扰有关外，还原环境下Eu2+和Sr2+之间的交换、氧化状态下Eu3+的存在形态可能分别对太灰水和四含水存在影响，但煤系水中最高的正Eu异常可能主要与斜长石的溶解有关。除围岩成分、温度及酸碱度之外，稀土元素无机形态可能对地下水稀土分异程度存在重要影响。含水层之间稀土元素特征的差异为水源识别提供了可行性，但仍需进一步的研究以待证实。

Rare earth element geochemical characteristics of the deep underground water from Renlou coal mine,northern Anhui Province

For better understanding the rare earth elements (REEs) characteristics and the water-rock interactions in deep seated environment, the REE compositions of three aquifers (Sihan, Meixi and Taihui aquifers) in Renlou coal mine, northern Anhui Province had been analyzed, the results indicate that these three aquifers are characterized by light REE depletion relative to heavy REE, significant positive Eu anomalies and universal negative Ce anomalies with different degrees. The negative Ce anomalies are related to oxidation-reduction potential. However, except for isobaric interference of BaO during analysis, the positive Eu anomalies of Taihui and Sihan aquifers are probably affected by exchange of Eu2+ and Sr2+ in reducing conditions and Eu3+ in oxidizing conditions, respectively, whereas the highest positive Eu anomalies of Meixi aquifer are considered to be related to dissolution of plagioclase. Additionally, inorganic complexation plays important role in controlling the REE fractionation of groundwaters besides wall rock composition, temperature and pH values. The differences of REE characteristics between these aquifers provide possibility for discrimination of water source by using REE, but further study is needed.