层间氧化带砂岩型铀矿稀土元素变化规律初探——以伊犁和吐鲁番—哈密盆地为例

A Preliminary Study on REE Transformation Regularities of the Interlayer Oxidation Zone in Sandstone-type Uranium Deposit: In Case of the Ili and Turpan—Hami Basins

本文以发育层间氧化带砂岩型铀矿的伊犁、吐鲁番—哈密盆地为例,详细研究了成矿层间氧化带稀土元素的分布特征和稀土元素在层间氧化作用中的变化规律。通过与北美页岩、还原带原生砂岩的对比,研究了稀土元素在不同氧化分带中的变化情况,结果表明在层间氧化作用过程中,稀土元素在总体亏损的背景上发生了明显的分异,LREE从氧化带到过渡带含量逐步降低,HREE由氧化带到过渡带趋于富集;δCe由氧化带到过渡带随氧化作用的减弱降低,δEu则逐步升高,呈现与表生风化作用相同的变化规律,较好地指示了层间氧化带中氧化—还原环境的变化。虽然稀土元素存在一定的迁移变化,但没有中亚砂岩铀矿床出现的REE显著迁移,高度富集现象。

This paper is base on the case of the interlayer oxidation zone sandstone uranium deposits in the Ili basin and Turpan--Hami basin, the author particularly study REE distributing characteristics and its transformation characteristics of ore-bearing interlayer oxidation zone. By the contrast of North American shale and original sandstone of deoxidization zone, research the REE transformation circumstances of different oxidation zone. It is indicated that at the process of interlayer oxidation the rare earth elements differentiate obviously with collectivity to the bed , LREE reduce at step from oxidized zone to transitional zone, the content of HREE rise at step from oxidized zone to transitional zone, δCe reduce from oxidized zone to transitional zone as the weakness of oxidation and δEu rise at the same time which present the same Transformation regularity as hypergene weathering, and all of these well indicate the change of oxidation and reducing environment. Although the REE occurs some transformation regularities, but the phenomena of notable transformation and high enrichment of REE in sandstone type uranium deposits in Middle Asia did not occur.