ЛИТОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА БАЛТСКИХ И САРМАТСКИХ ПЕСКОВ МЕЖДУРЕЧЬЯ САВРАНКИ И КОДЫМЫ КАК ВОЗМОЖНЫХ КОЛЛЕКТОРОВ НАКОПЛЕНИЯ ТЯЖЕЛЫХ МИНЕРАЛОВ

Abstract

The lithological composition of the Miocene-Pliocene sand deposits of the Middle Sarmatian and Baltian age between the rivers of the right tributaries of the Southern Bug (Savranka and Kodima rivers) was studied. Two series of sand are described in the composition of the Middle Sarmatian deposits. Under-limestone series has cross-bedding, which alternates with horizontal bedding. There are medium and coarse-grained sands with medium and good grading; there are layers of unsorted sandy-aleurite-clay material with a significant content of fine gravel. Garnet, magnetite, titanium-magnetite, ilmenite, rutile, glist predominate in the heavy fraction. Under-limestone series of the Middle Sarmatian is formed in coastal conditions with a flow hydrodynamic regime. Upper-limestone series of the Middle Sarmatian is composed of well-sorted medium-grained sands with an insignificant admixture of silt. The series is characterized by well-developed drift structure, expressed over tens of kilometers. The sands are enriched in heavy fraction, there are thin layers of black sand. Garnets, titanomagnetite, magnetite, ilmenite, rutile, glist predominate in the heavy fraction. Series is formed in the delta conditions that were established during the regression of the Sarmatian sea basin. The Baltian suite, which is the deposits of the Meotian, Pontian, Cimmerian and Akchagilian levels of the Miocene and Pliocene, was formed in continental conditions. The series is characterized by the alternation of aleurite-clay and sandy sediments, the presence of ironification, the wide distribution of clastogenic and authigenic postsedimentation carbon-bearing . The Baltian sands are predominantly fine-grained, sometimes clayey-silty, medium and well graded. Heavy minerals contain large quantities, among which ilmenite, titanium-magnetite, magnetite, garnet, zircon, and glist predominate. The Baltian suite was formed in the conditions of the alluvial plain that existed on the southern slope of the Ukrainian Shield in the Miocene-Pliocene. Compared to the Sarmatian deposits, Baltian sediments show a sharp increase in the amount of titanium-containing minerals and glists, this may be due to the erosion of new ore bodies with a decrease in the basis of erosion as a result of tectonic uplifting of the territory. The results of the study of the lithological composition and heavy fraction of Sarmatian and Baltian sandy sediments can be useful when searching for primary titanium-magnetite deposits, as well as when searching for alluvial placers on the right bank of the Southern Bug. In addition, such studies help in the reconstruction of alluvial pathways for the transfer of ore matter in the hypergenesis zone in the Northern Black Sea region.