二连盆地哈达图铀矿床赛汉组上段物源分析

Sediment Source Analysis for the Upper Member of Saihan Formation of Hadatu Uranium Deposit in the Erlian Basin

哈达图铀矿床位于二连盆地乌兰察布坳陷的齐哈日格图凹陷内,下白垩统赛汉组上段为主要含矿层位。目前该矿床已完成普查阶段找矿工作,成果颇丰,但是其赛汉组上段沉积物的物源、物源与铀源时空关系等认识仅停留在初步推测阶段,缺少系统的研究与归纳。文章通过对哈达图铀矿床赛汉组上段岩石学及沉积体系特征研究,结合赛汉组上段砂岩与周边源区不同类型岩石的地球化学特征对比分析,初步认为哈达图铀矿床赛汉组上段物源主要来自苏尼特隆起中的花岗岩,其次为火山岩及变质岩,还有赛乌苏及塔木钦凸起侧向补给;同沉积期初始富集的铀元素在层间氧化阶段迁出构成了重要的铀源。

Erlian Basin in Inner Mongolia is an important uranium-producing basin in northern China.A large number of uranium deposits have been discovered in the basin.Among them,the Hadatu uranium deposit is located in the Qiharigetu sag,Wulanqab Depression,Erlian Basin,and the main ore-bearing layer is the upper member of Lower Cretaceous Saihan Formation.At present,the prospecting work of this deposit has been completed in the census stage,and the prospecting results have been quite fruitful.However,the knowledge of the provenance,the temporal and spatial relationship between the provenance and the uranium source of the sediments in the upper Saihan Formation of the Hadatu uranium deposit is only at the preliminary stage,and lack of systematic research and summary.Based on the petrological and sedimentary system characteristics,combined with the analysis of the geochemical characteristics of the sandstones and the types of rocks in the surrounding source areas,this paper preliminarily concluded that the provenance of the upper member of Saihan Formation of the Hadatu uranium deposit mainly comes from the granite in the Sunite uplift,followed by metamorphic rocks and volcanic rocks,and lateral supply from the Saiwusu and Tamuchin uplifts.The initially enriched uranium element during the syn-deposition period migrated out in the interlayer oxidation stage and constituted an important uranium source.