Lithostructural Geological-Genetic Model and Mineral Composition of the Krasnokutsk Rare Metal–Titanium Placer Deposit (Ukraine)

Resumo

The paper presents the geological setting, structure, lithology, and placer-controlling factors in the Krasnokutsk placer rare metal–titanium deposit located in Miocene sediments on the northeastern slope of the Dnieper-Donets Depression. The identified lithofacies (alluvial-deltaic, coastal- and shallow-marine, eolian) complexes correspond to the lower (Aquitanian), middle (Burdigalian), and upper (Langian) subformations of the Miocene Novopetrovsk Formation. Placer bodies are confined to the littoral coastal-marine complexes of the middle Novopetrovsk subformation. Placer formation is related to coastline stabilization phases at the regressive stage of the Sub-Paratethys Basin existence. The main prospecting criteria for the identification of promising sectors in the Kharkov–Sumy placer zone are: coastline stabilization areas of the regressive stage of the middle Novopetrovsk basin evolution and development of transverse alluvial-deltaic structures that delivered into the basin low-metalliferous sediments, which distorted the monotonous pattern of alongshore transport and played the role of structural-sedimentational traps. The developed digital lithostructural model of the Krasnokutsk deposit makes it possible to propose a criterion complex for a comparative assessment of different sectors of the deposit to define the priority order of their development. The mineral composition of productive rocks is typical of placers for the study region and rare metal–titanium placers in general. Increased rutile and zircon contents, which augment the industrial value of placers in this zone, are related to the influence of crystalline rocks of the Voronezh Massif.