包婷婷

摘 要：稀土元素因独特的化学性质通常被用来指示地质体的环境演化过程。系统采集新集二矿四个含水层（二含水、砂岩水、太灰水、奥灰水）地下水样品共13个水样，测试样品中稀土元素含量，模拟其无机络合形态，来探讨不同含水层稀土元素地球化学特征及其控制因素。结果表明：研究区四个含水层地下水均表现为中稀土元素富集，呈现明显的Eu正异常和Ce负异常;不同含水层在轻重稀土分异程度上存在明显区别，Ce负异常主要与氧化还原条件和围岩岩性条件有关，Eu正异常与斜长石的溶解作用和高含量Sr有关;MINTEQ模拟结果显示，研究区地下水的无机络合形态主要以Ln（CO3）-2和LnCO+3为主。

关键词：地下水;稀土元素;地球化学特征;MINTEQ

Abstract：Rare earth elements are usually used to indicate the environmental evolution processes of a geologic body for their unique chemical properties. The purpose of this study is to discuss the geochemical characteristics and controlling factors of rare earth elements in different aquifers. 13 groundwater samples of four aquifers （the second aquifer of the Quarternary， the sandstone aquifer， the Taiyuan Formation limestone aquifer and the Ordovician limestone aquifer）in Xinji No.2 mine were collected for testing. The content characteristics and influencing factors of rare earth elements in different aquifers were discussed. The results indicated that these four aquifers were characterized MREE enrichment relative to LREE and HREE， with significant positive Eu anomalies and universal negative Ce anomalies in different degrees. Among them， Ce depletion were mainly related to the environment of redox and lithology of surrounding rock， and positive Eu anomalies related to dissolution of plagioclase and excessive Sr in groundwater. The simulation results showed that Ln（CO3）-2 and LnCO+3 were the main inorganic complexes in groundwater.

Key words：groundwater; rare earth elements; geochemistry; MINTEQ

稀土元素以其穩定且相似的地球化学性质、独特的地球化学行为被广泛应用于示踪岩浆热液作用、地壳演化、风化过程、古气候变化及水岩相互作用等各种地球化学过程，是当前元素地球化学领域的重点研究方向之一[1-5]。稀土元素在水中的溶解度较低，在风化、剥蚀、搬运、再沉积及成岩过程中，由于不同地球化学过程的细微差异可以导致元素发生富集与亏损[6]。地下水中溶解态稀土元素的浓度很低且不同含水层之间的差异较大[7]，这对了解水体中稀土元素的化学行为具有重要意义。

一些研究者针对不同类型地下水稀土元素开展过研究。文献[8]通过对瑞士东部某地区浅层地下水、过度开采地段地下水和基……