摘要
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 。
This paper discussed in detail on the REE component and the characteristics of the different kinds of attapulgite clay ores as well as basalts, weathered basalts in four localities of attapulgite clay deposits of Jiangsu and Anhui provinces of China. It is concluded that the half-weathered basalts have not distinct REE fractionation and strong weathered basalts had HREE loss in the process of the basalts weathered to form smectite family minerals. And the lateritic montmorillonite clays that form from the basalts weathering have a distinct Ce positive anomaly, a little MREE loss and LREE and HREE renew enrichment. That reflects the particular oxidation condition in the Earth′s surface and the adsorption of the colloid solution of the lake water in the basin of the continent in the time the clays formed. The attapulgite clays that are products of the reaction between basalts with lake water in the original place of the basin have same characteristics as that of the basalts and the weathered basalts. This shows that REE does not transfer heavily in the progressive chemical weathering process. The sedimentary attapulgite clays have also a similar REE component and characteristic parameters to the basalts and the weathered basalts, and have a distinct Eu negative anomaly and a big value of LREE/HREE, which shows that the sedimentary clays come from the weathered basalts, and REE partitioning patterns characters of the clays are controlled by the residual material of the weathered basalts.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2002年第5期463-467,共5页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金 ( 4 0 0 72 0 17)
国土资源部项目 ( 2 0 0 70 8B2 )
