稀土淋失量与水动力条件变化关系的研究

用稀土数据对岩溶学方面的研究,迄今尚未见报道。本文对典型喀斯特洞穴粘土沉积物中的稀土淋失量与沉积环境中的水动力条件变化特征进行研究。该洞穴由潜流洞向水面洞演化过程中,因水动力条件变化,水量和流速由大变小,其粘土沉积物中的稀土淋失量也相应由大变小。稀土淋失量主要为铈族稀土量的损失,钇族稀土变化不大.各个样品的稀土分布模式完全一致,且以铈族稀土为主,基本上没有发生分异。这些特点表明:洞穴各个演化阶段的粘土沉积物的物源地相同,且搬运距离不远。样品的稀土解析实验和稀土水解实验表明,稀土主要呈类质同像存在,次呈离子吸附态存在。沉积和淋滤为弱酸性至中性环境。

A STUDY ON THE RELATIONSHIP BETWEEN THE AMOUNT OF REE LEACHING AND Loss CHANGES OF HYDRODYNAMIC CONDITIONS

Studies are acomplished in this paper on the amount of REE leaching loss from clay sediments in a typical Karst cave and the characteristics of hydrodynamic variation in the sedimental environment. During the evolution process from phreatic cave to water table cave caused by the cave's hydrodynamic variation, the volume and rate of the flow reduced, and the leaching loss of the REE from clay sediment is also decreased correspondingly. The leaching amount is mainly characterized as the loss of Cerium group elements of REE, and the variation in the elements of Ytrium group is not remarkable . The REE distribution patterns of each sample are completely consistent, and the elements of Cerium group are dominant, in which no differentiation happened. From these characteristics, it can be concluded that there is the same material resource of the clay sediments during each evolution period, and the distance of trans portation is not long. The REE analytic and hydrolytic experiments of the samples show that the REE exist mainey in isomorphic state and secondly in ionic adsorption state, the sedimentation and the leaching process of the clay mineral happened in the sedimental environment of weak acid property.