研究了苏皖四处凹凸棒石粘土矿床不同类型矿石的稀土元素组成及其变化特征。研究表明玄武岩首先风化形成蒙皂石族粘土矿物 ,在此过程中稀土元素没有明显的分馏作用 ,强风化的玄武岩重稀土元素强烈亏损 ;如果玄武岩在地表进一步风化形成红土型蒙脱石粘土 ,则发生明显的铈正异常 ,中稀土亏损而轻稀土和重稀土又重新富集 ,这反映了当时大陆地表特殊的氧化条件和盆地湖水溶液的胶体吸附作用。玄武岩在原地进行水 岩作用 ,发生递进化学风化 ,其稀土元素地球化学特征与玄武岩及其风化产物的稀土元素地球化学特征基本一致 ,总量略低 ,显示REE没有大量迁移流失。沉积型凹凸棒石粘土的稀土元素地球化学特征也与玄武岩及其风化产物的稀土元素地球化学特征相似 ,但同时表现出轻重稀土比值增大 ,铕正异常 ,表明沉积型凹凸棒石粘土的物源基本上是来源于玄武岩的风化产物 ,但REE配分模型受玄武岩风化残积物的制约 The REE composition and its variation characteristics of four types of attapulgite clay deposits in Jiangsu and Anhui Provinces were studied. The study shows that the basalt firstly weathered to form smectite group clay minerals. In this process, the rare earth elements have no obvious fractionation effect, and heavy weathered basalt heavy rare earth elements are strongly depleted. If the basalt further weathering forms terracotta clay, Significant cerium positive anomalies, loss of rare earths and light rare earths and heavy rare earths were re-enriched, reflecting the special surface oxidation conditions of the continent at that time and the colloidal adsorption of lake water solution in the basin. Basalt undergoes water-rock interaction and progressive chemical weathering. The REE geochemical characteristics are basically the same as the REE geochemical characteristics of basalt and its weathering products. The total amount is slightly lower, indicating that there is not a large amount of REE migration and loss. The REE geochemical characteristics of the attapulgite clay are also similar to the REE geochemical characteristics of the basalt and its weathering products, but at the same time, the ratio of light to heavy rare earths is increased and the positive Eu anomaly, indicating that the sedimentary attapulgite clay The source is basically a weathering product derived from basalt, but the REE partition model is governed by basalt weathering residues