New Insights into the Genesis of Dibrova U-Th-REE Mineral Deposit (West Azov Megablock, Ukraine) Using Monazite Chemistry

This paper investigates the monazite grains from Dibrova rare-earth-thorium-uranium (U-Th-REE) mineral deposit within Azov Megablock of Ukrainian Shield. U-Th-REE mineralization is associated with K-feldspar-quartz metasandstones and metagritstones (hereafter quartzites) pegmatoids. The latter possibly represent products ultrametamorphism/granitization initially sedimentary clastic rocks during tectono-magmatic activation Paleoproterozoic. Ores are composed quartz as a principal mineral, feldspar, sillimanite, muscovite, monazite, brannerite, uraninite, zircon, rutile, sulfides. purpose this work was to obtain insights into genesis by studying grains, their chemistry, ages. Petrographic research carried out that included studying/analyzing monazites various monazite-bearing (quartzites, pegmatoid, biotite schist samples). A variety methods tools were used, including optical microscopy study, X-ray fluorescence (XRF) mapping selected samples, well scanning electron microscope (SEM) microprobe (EPMA) characterization monazites, U-Th-Pb chemical dating. U-Pb-Th dating yielded two major distinct age groups at 3.0–2.8 Ga 2.2–2.0 Ga. first group corresponds time formation Archean granitoids, which served source for its sedimentation Paleoproterozoic in suite sediments. second reprecipitation (i.e., remobilization) activation. location deep mantle-crustal Devladivska shear zone another favorable factor remobilization transport metals. New data on yield more complete understanding geological history complex polyphase rare-earth-uranium-thorium deposit.