鄂尔多斯盆地东北部直罗组古层间氧化带 形成机制探讨

鄂尔多斯盆地东北部是我国重要的砂岩型铀矿成矿带之一，蕴藏着丰富的铀资源。通过研究发现，区内铀矿床与古层间氧化带具有非常紧密的联系。通过对纳岭沟、大营铀矿床直罗组下段古层间氧化带中各后生蚀变砂岩与原生砂岩的物质成分及地球化学指标的研究，发现绿色砂岩与灰色砂岩在物质成分上的主要区别体现在黏土矿物、方解石及黄铁矿含量上，并且不同蚀变类型砂岩具有其各自的地球化学指标特点。基于对古层间氧化带中各后生蚀变的研究，初步探讨了古层间氧化带的形成机制。这一成果为深化本区铀成矿机理、建立区域铀成矿模式提供了重要的理论依据。

Study on Formation Mechanism of Epigenetic Altered Zone in Zhiluo Formation,Northeastern Ordos Basin,North China

The area of northeastern Ordos Basin, which is rich in uranium resource, is one of the important metallogenic belts for sandstone type uranium deposits in China. Previous study shows that uranium mineralization here is closely related to paleo interlayer oxidation. On the basic study of material composition and geochemical index of each epigenetic altered sandstone and original sandstone in paleo interlayer oxidation zone in Zhiluo Formation, it can be concluded that the main differences of material composition between green sandstone and gray sandstone are the content of clay minerals, calcites and pyrites. Moreover, the sandstone has its own characteristic of epigenetic alteration in different altered type. Finally, the formation mechanism of paleo interlayer oxidation has been discussed in this paper through the research of each epigenetic altered sandstone features which provides an important theoretical basis for deepening the uranium mineralization mechanism and establishing regional uranium metallogenic model in the study area.