巴音戈壁盆地含矿目的层沉积相特征与砂岩型铀矿化的关系

重点论述了盆地3处铀矿床（点）含矿层早白垩世巴音戈壁组上段沉积相展布特征及其与铀矿化的关系。认为该地区铀矿化发育主要受两种沉积环境控制：（1）受扇前辫状分流河道控制,该沉积环境内发育厚层砂体,具有泥-砂-泥结构,在潮湿、湿热古气候环境下,该沉积环境内的砂体中富含有机质和炭屑,有利于铀成矿;（2）受各类沼泽沉积环境控制,在潮湿、湿热古气候环境下,该地区发育大面积沼泽,沼泽沉积环境中多为泥炭、泥质岩及碳质岩沉积,有利于铀元素的吸附、沉淀、富集并成矿。受控于两种沉积环境,该盆地内砂岩型铀矿化矿体存在两种表现形式：卷状及板状。其成因为层间氧化作用与同生沉积富集共存。

Sedimentary facies characteristics of ore-bearing target horizon and its relationship to sandstone-type uranium mineralization in Bayingebi Basin

Sedimentary facies distrib ution characteristics of the upper member of Early Cretaceous Bayingebi Formation and its relationship with uranium mineralization are studied with focus in three deposits （ore occurrences） in Bayingebi Basin. It is considered that the development of uranium mineralization of the basin is mainly controlled by two sedimentary environments：（1）braided distributary channel on fan-delta front which developed in humid and hot palaeo-climatic environment and produced clay-sand-mud strata with thick layered sand bodies rich in organic matter and carboniferous debris which are beneficial to sandstone-type uranium mineralization;（2）different types of marsh of large area which envolved in humid and hot palaeo-climate and bear a large amount of peat,argillite and carbonaceous rock which are beneficial for uranium adsorption,precipitation and enrichment. Controlled by two kinds of sedimentary environments,uranium ore bodies in this basin are of roll-type and tabular-type,and the minearalization is the coexistence of inter-layered oxidation and syngenetic sedimentary enrichment.