Ore-bearing of the osynova area of the Mezhyrichne deposit of titanium ores
Authors:   Institute of Geological Sciences of the National Academy of Sciences of Ukraine, Figura L.A. , Kovalchuk M.S. ,   Institute of Geological Sciences of the National Academy of Sciences of Ukraine
Published: December 2022

Information on the geological structure and ore bearing of the Osynova area of the Mezhyrich deposit of titanium ores, which is located in the northeastern part of the Volodar-Volyn massif of the Korosten pluton and is part of one of the most promising Volyn zirconium-titanium ore districts, is presented. It was found out that the ore-bearing potential of the Osynova area is determined by a spatially and paragenetically connected ore system, which is composed of titanium-bearing rocks of the crystalline basement of the Volodarsk-Volyn complex, their weathering crusts, continental (irshan suite, apt-albian) and marine (moshno-rudnyan suite, turon) by products of erosion and redeposition of eluvium. Based on the coordinates of the wells, their description, and test results, a target database was created, which became the basis for cartographic constructions. Maps of the relief of the top, bottom and the thickness of mesozoic-cennozoic eluvial kaolins were created; redeposited kaolins and apt-albian sands; sand-silica horizon of turon. It was found that in most cases there is a direct correlation between the relief of the bottom and the top of the ore-bearing deposits. As a rule, there is an inverse correlation between the thickness of deposits and the relief of their bottom and top. A set of maps was created showing the lateral distribution of average ilmenite contents in eluvial kaolins, continental and marine aptian-albian and turonian sediments. The lateral distribution of the average ilmenite contents in the sedimentary cover formations of different ages and genetics is uneven and characterized by significant contrasts (in eluvium — 0.4-57.2 kg/m3; in apt-albian sands — 1.0-162.58 kg/m3; in re-deposited apt-albian kaolins — 1.5-125.48 kg/m3; in sand-silica horizon of the turonian — 0.6-45.57 kg/m3). The best correlation exists between weathering crust formations and aptian-albian alluvial deposits. In the deposits lying above the geological section, the correlation with the eluvium is lost. The study of the distribution of the ilmenite content in the vertical cross-section of the wells showed that the ilmenite content in the sands is uneven with one or several levels of maximum enrichment. For example, in the vertical section of the sands (from bottom to top) there are layers with different contents (kg/m3) of ilmenite: 53.0-57.0; 27.0-37.0; 39.0-41.0; 10.0-23.0; 5.2-13.3; 27.0-68.2; 7.6-9.9; 49.0-56.0. On the other hand, in redeposited kaolins, the content of ilmenite in the vertical section is mostly uniform; sometimes one distinct level of maximal enrichment is present (rarely two such levels are present). For example, with a predominant ilmenite content of 27.0-32.0 kg/m3, in the lower and upper parts there are layers with a content of 48.0-63.0 kg/m3 and 42.0-68.0 kg/m3, and in the middle part of the formation, the content is 193.0-199.6 kg/m3.In Turonian sand-silica rocks, the maximum ilmenite content is located in the lower part of marine sediments.