海拉尔盆地是近几年发现可地浸砂岩型铀矿找矿潜力较大的地区之一，目前已在海拉尔盆地西南部的克鲁伦凹陷内发现较好的铀矿化，含矿目的层为下白垩统伊敏组。利用扫描电镜、X射线衍射及电子探针分析等手段对研究区伊敏组砂岩的黏土矿物相对含量、微观特征及铀矿物的赋存形式进行研究。结果表明：克鲁伦凹陷黏土矿物主要为绿泥石，次为高岭土、蒙脱石及伊蒙混层。铀的存在形式主要为铀石，次为吸附状态铀和少量沥青铀矿。研究区的蒙脱石、高岭石与绿泥石存在相互转化现象，在碱性条件下，存在Ca²⁺、Mg²⁺、Na⁺时部分蒙脱石向绿泥石转化，在Fe²⁺、Mg²⁺存在时，部分高岭石向绿泥石转化。黏土矿物的蚀变为研究区铀石的形成提供了局部碱性环境。

Hailaer Basin is one of the areas with great prospecting potential for in-situ leachable sandstone-type uranium deposits found in recent years. At present, good uranium mineralization has been found in the Kelulun Sag in the southwest of Hailaer Basin, and the ore-bearing target layer is the Lower Cretaceous Yimin Formation. Scanning electron microscopy, X-ray diffraction and electron probe analysis were used to study the relative content of clay minerals, microscopic characteristics and occurrence forms of uranium minerals in the sandstone of Yimin Formation in the study area. The results show that the clay minerals in the Kelulun Sag are mainly chlorite, followed by kaolin, montmorillonite and illite-montmorillonite mixed layer. Uranium mainly exists in the form of uranium stone, followed by adsorbed uranium and a small amount of pitchblende. Montmorillonite, kaolinite and chlorite in the study area have mutual conversion phenomenon. Under alkaline conditions, when Ca²⁺, Mg²⁺ and Na⁺ exist, some montmorillonite is converted to chlorite. When Fe²⁺ and Mg²⁺ exist, some kaolinite is converted to chlorite. The alteration of clay minerals provides a local alkaline environment for the formation of uranium in the study area.