Abstract

The Shulepovo refractory clay deposit was discovered in the 1970s. It consists of subhorizontal kaolinite lenses located at different depths (1–20 m) in a clay–sand sequence tentatively assigned to the Neogene or, possibly, Late Pliocene (?). Application of the X-ray diffraction method coupled with the UV-VIS-NIR spectroscopy established an almost monomineral composition of lenses, with a minimal (not more than 5%) content of quartz, as well as admixture of halloysite and mixed-layer smectite–vermiculite. Calculation of the Hinckley index (HI) for kaolinite revealed a high ordering degree, suggesting its mainly authigenic origin. The bulk chemical composition of kaolinite samples is close to that of pure kaolinite, with an insignificant (not more than 2%) Fe and Ti. Zonation in the chemical composition alteration was not detected within the lens. Studies of the host sand–clay sequence revealed that it can be assigned to the alluvial (channel and oxbow) facies. The formation model of kaolinite lenses in the Shulepovo deposit includes the following processes: major transformations of the terrigenous–clastic kaolinite in stagnant waters, its crystallization, and formation of the authigenic kaolinite due to the decomposition of the clastic aluminosilicate minerals in a chemically aggressive medium.

中文翻译：

---

Shulepovo 矿床（梁赞地区，俄罗斯中欧）耐火粘土的矿物学地球化学特征、成因和年龄

摘要

Shulepovo 耐火粘土矿床发现于 1970 年代。它由位于不同深度（1-20 m）的亚水平高岭石透镜体组成，位于粘土-砂层序列中，初步归属于新近纪或可能是晚上新世（？）。X 射线衍射法与 UV-VIS-NIR 光谱相结合的应用建立了几乎单一矿物组成的镜片，其中石英含量最少（不超过 5%），以及埃洛石和混合层蒙脱石的混合物——蛭石。计算高岭石的欣克利指数 (HI) 显示出高有序度，表明其主要是自生成因。高岭石样品的整体化学成分接近纯高岭石，Fe 和 Ti 含量微不足道（不超过 2%）。在镜片内未检测到化学成分变化的分区。对宿主砂粘土层序的研究表明，它可以归属于冲积层（河道和牛弓）相。Shulepovo矿床高岭石透镜体的形成模式包括以下过程：陆源-碎屑高岭石在死水中的主要转化、结晶，以及碎屑铝硅酸盐矿物在化学侵蚀性介质中分解形成自生高岭石。 .