法国洛德夫盆地砂岩型铀矿床成因分析

Genetic analysis of sandstone type uranium deposits in Lodeve Basin,France

洛德夫(Lodeve)盆地位于法国(France)中央地块(Massif Central)南缘,盆地内砂岩型铀矿床主要分布在盆地北部,主要为构造-岩性控制型砂岩型铀矿床。在综合前人研究的基础上,分析了洛德夫盆地砂岩型铀矿床的成因模式。盆地内砂岩型铀矿有三种铀矿化,铀矿化主要受构造控制,盆地内ENE-WSW向断裂为主要控矿构造;矿化同时也受控于岩性,含矿层均位于二叠系奥顿阶(Autunian)中下部。在此基础上盆地内铀矿成因较为复杂,受多种因素影响,铀成矿具有成岩早期还原吸附、成岩晚期富集沉淀及后生热液成矿三种成因,分别与三种铀矿化相对应。

Lodeve Basin is located on the southern edge of the Massif Central in France and the sandstone type uranium deposits in the basin are mainly distributed in the north,the sandstone type uranium deposits in the basin are mainly tectonic-lithologic controlled sandstone type uranium deposits.On the base of previous studies,the genetic model of sandstone type uranium deposits in Lodeve basin were analyzed.There are three types of uranium mineralization of sandstone type uranium deposits in the basin,the uranium mineralization is mainly controlled by structure,the ENE-WSW fault in the basin is the main ore-controlling structure;mineralization is also controlled by lithology and the ore-bearing horizons are located in the lower part of the Permian Autunian stage.The genesis of uranium deposits is complex and affected by many factors,the deposit was formed by three process;early diagenesis reduction adsorption process,late diagenesis enrichment sedimentation process and epigenetic hydrothermal fluid mineralization process,which correspond to the three types of uranium mineralization.