STRUCTURAL AND LITHOLOGICAL MODEL OF THE DUBRIVSKY DEPOSIT OF ALKALINES ELUVIAL KAOLIN

Abstract

Information on the Dubrivske alkaline eluvial kaolin deposit, located in the Baranivka district of the Zhytomyr region and a part of the Dubrivksko-Khmelivsky kaolin district, is reviewed. Based on the results of generalization and analysis of materials of production reports of different years, zoning and material composition of the weathering crust within the deposit are established. Weathering crust was formed due to hypergenic changes of granites, pegmatites, migmatites, gneisses. The thickness of the eluvium varies from a few tens of centimeters to 42.7 m. The sequence and stages of weathering of crystalline rocks of the foundation were reflected in the vertical zonation of the weathering crust and the material composition of its zones. The profile of the weathering crust consists of three zones (bottom up): disintegration and leaching; initial hydrolysis (kaolinite-hydromica); final hydrolysis and oxidation of weathering products (kaolinite). Based on the coordinates and description of the wells, the relief of the bottom and surface of the kaolin deposit, as well as the lateral change in their thickness, were investigated. It was found that the kaolin deposit has a complex internal structure and morphology. The thickness of the kaolin deposit has an inverse correlation with the relief of its base, so that the increased areas of the base correspond to small thicknesses of kaolin and vice versa. Based on the results of well testing and chemical analysis of kaolins, the distribution of oxides of iron, titanium and whiteness in the vertical section of kaolins was investigated, and the lateral distribution of the contents of oxides Al2O3, Fe2O3 and TiO2 was established. It was found that in some areas of the lateral distribution of eluvial kaolins, the contents of Fe2O3 and TiO2 have a direct or inverse correlation. The whiteness indices of eluvial kaolins in the vertical section have significant variability and predominantly a direct correlation with the content of iron and titanium oxides, or with one of these indicators. In almost all wells there is a regular decrease in the whiteness index with depth. An inverse correlation was established between the Al2O3 content and the Fe2O3 content and only in some areas with the TiO2 content. Data on the average content (in %) of basic oxides within individual areas of subsoil use of the Dubrovskoye deposit are given. In general, the deposit is characterized by heterogeneity of the base, surface, and the thicknessand the content of rock-forming oxides in the vertical section and laterally.