江西相山铀矿田居隆庵矿床钍元素地球化学特征研究

Research on Geochemical Characteristics of Thorium for Julong,an Deposit,Xiangshan Ore Field

居隆庵矿床是江西相山铀矿田西部的一个大型铀-钍混合矿床,通过对一系列蚀变(围岩)及矿化样品的元素地球化学分析,详细讨论了与钍矿化有关的主量及微量元素的特征。钍元素富集的样品中,主量元素的总体特点是富钙、富磷,且Na2O>K2O。在早期碱交代阶段,往往只形成单铀型矿化,而钍矿化主要形成于铀-萤石、水云母化阶段。蚀变和矿化样品的稀土元素分配形式不同,钍矿化与稀土元素特别是重稀土元素高度相关,微量元素Re,Y,Se,Pb与钍矿化高度相关,揭示钍矿化形成与金属硫化物及磷钇矿等磷酸盐密切相关。

Julong＇an is a large-sized mixed uranium and thorium deposit in the western Xiangshan ore field, Jiangxi Province. On the basis of systematic geochemical analysis, this paper discusses distribution characteristics of both trace and major elements associated with thorium mineralization in detail. The major elements of Th-rich samples are rich in calcium and phosphorus, and characterized by Na2O〉K2O. The mono-uranium mineralization is always developed in the early stage of alkali alteration, and the thorium mineralization is mainly concentrated in the later stage of pitchblende-fluorite-hydromica alteration halo. The distribution patterns of rare earth elements in wall rocks and mineralized samples are different. The thorium mineralization is highly associated with rare earth elements, especially with the heavy ones. Trace elements such as Re, Y, Se, Lu are highly correlated with thorium mineralization due to formation of associated sulfides and phosphates, such as xenotime.