下庄铀矿田微量元素和稀土元素地球化学特征  

Trace and REE Elements Geochemical Characteristics of Xiazhuang Uranium Ore-field

作　　者：刘文泉 

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]核工业二九0研究所,广东韶关512029

出　　处：《稀土》2017年第5期92-102,共11页Chinese Rare Earths

基　　金：中国核工业地质局项目(201367)

摘　　要：下庄铀矿田是我国最大的花岗岩型铀矿田,本文在详细的野外勘察基础上,对矿田下庄岩体、帽峰岩体以及不同矿化类型(硅化碎裂岩型、蚀变碎裂花岗岩型和碱交代型)矿石的微量元素和稀土元素进行系统分析。结果表明,下庄岩体和帽峰岩体富集大离子亲石元素Rb和稀土元素Ce、Sm、Y,明显亏损Ba、Sr和轻微亏损Nb、Ta,具有较高的Rb/Sr比值和较低的Nb/Ta比值,表明下庄岩体和帽峰岩体高度成熟的地壳演化特征。硅化碎裂岩型和碎裂蚀变花岗岩型矿石Zr亏损明显,反映矿石形成过程中有地壳物质混染;各类型矿石稀土总量ΣREE、Sm-Nd图解、轻-中-重稀土元素三角图解反映出成矿流体运移过程中萃取了不同岩石中的稀土元素,矿石稀土元素主要继承了围岩中稀土元素特征,铀矿田成矿过程处于一个连续的热液体系中。The Xiazhuang uranium ore field is the biggest granitic-type uranium ore field in China. Based on the detailed field investigation, this article systematically analyzes the trace elements and rare earth elements of Xiazhuang granite, Maofeng granite as well as different mineralization types ore （silicified cataclastic type, cataclastic granite type and alkaline metasoma- tite type ）. The results show that the samples of Xiazhuang granite and Maofeng granite are enriched in large ion lithophile ele- ments Rb and rare earth elements Ce, Sin, Y, and obviously depleted in Ba, Sr, P, Ti, and slightly depleted in Nb, Ta, with high Rb/Sr and low Nb/Ta ratio. All of these indicates the highly matured characteristics of crust evolution in Xiazhuang granite and Maofeng granite . The heavy depletion in Zr of silicified cataclastic type ore and cataclastic granite type ore reflects the crustal material contamination in ore forming process. The total rare earth amount ]~REE ,Sm-Nd graphic, and triangle diagram of light-middle-heavy rare earth dements from all type of ores reflect that rare earth elements of ore fluid were extracted from different rocks in the process of ore-forming and the ore rare earth elements mainly inheritance host rock rare earth elements feature. The uranium ore - forming process is in a continuous hydrothermal system.

关 键 词：下庄铀矿田 微量元素 稀土元素 物质来源 

分 类 号：P595[天文地球—地球化学]