CHEMICAL COMPOSITION AND LATERAL DISTRIBUTION OF ILMENITE AND ITS ALTERED VARIETIES IN THE SITES OF YEMYLIVSKA AND SEREDNIA OF THE MEZHYRICHNE TITANIUM DEPOSIT (ZHYTOMYR REGION)

Abstract

The chemical composition of ilmenite from Lower Cretaceous alluvial kaolin sands of the Irshanska suite in the Yemylivska and Serednia sites of the Mezhyrichne titanium ore deposit (Volynskyi megablock of the Ukrainian Shield) was studied. This made it possible to identify its variations in different areas and perform a comparative analysis. Correlation analysis determined the direction and strength of correlations between oxides in ilmenite, as well as common patterns and significant differences in the relationships between oxides. The strong negative correlation between FeO and Fe₂O₃ and the positive one between TiO₂ and Fe₂O₃ reflects the balance between the reduced and oxidized forms of iron in ilmenite. Two approaches were used to separate magmatic ilmenite, pseudorutile, and leucoxenized ilmenite: (1) by the FeO/Fe₂O₃ ratio, which allows for rapid classification of grains; (2) by combining the specified ratio with absolute concentrations of FeO and Fe₂O₃, which provides a more accurate interpretation. Thanks to this approach, the presence of both primary magmatic ilmenite and its altered varieties formed under exogenous conditions was confirmed. A comparative analysis of the processes of pseudorutilization and leucoxenization of ilmenite within the Yemylivska and Serednia sites was performed. Fractal analysis of the spatial distribution of magmatic ilmenite and its altered varieties showed that their distribution has signs of self-similarity and structural organization, which reflects natural processes of differentiation and secondary alteration. Cartographic modelling of the distribution areas of ilmenite of different chemical composition and with different FeO/Fe₂O₃ ratios was performed, which makes it possible to determine the degree of exogenous transformation, predict the distribution areas of ilmenite with different qualitative characteristics, reconstruct the conditions of placer formation, and optimize the industrial development of residual reserves within the studied areas. The proposed comprehensive model integrates chemical, mineralogical, and spatial data, providing a deeper understanding of the genesis of ilmenite placers, their chemical zoning, and potential for industrial development.