川北砂岩型铀矿稀土元素特征及铀成矿作用

REE characteristics and uranium metallogengsis of sandstone-type uranium deposits in northern Sichuan

在大量取样分析的基础上 ,本文系统分析研究了围岩、矿石、方解石脉和铀矿物的稀土元素组成 ,讨论了岩石、矿石沉积和成岩过程中的稀土元素变化规律 ,总结了川北砂岩型铀矿床的稀土元素地球化学特征。通过与典型的火山岩型和变质岩型热液成因铀矿床进行对比 ,认为川北砂岩型铀矿具有热液 (水 )改造成矿作用的稀土元素地球化学特点 ;铀矿化经历了沉积成岩和热液改造富集两个阶段。

On the basis of the analysis of a large number of samples at sandstone?type uranium deposits in northern Sichuan,this paper analyses the REE composition of country rocks,ores,calcite?veins and uranium minerals,and systematically summarizes their REE geochemical characteristics,and discusses variation regularity of REE during depositional and diagenetic processes.By comparing these characteristics with those of typical hydrothermal volcanics?type and metamorphic rock type uranium deposits both at home and abroad,authors suggest that sandstone?type uranium deposits in northern Sichuan are characterized by REE geochemical features of hydrothermal reworking metallogenesis,the uranium mineralization has experienced two stages:the diagenetic preconcentration and the concentration of hydrothermal reworking.