DIBROVSKOE URANIUM-TORIUM-RARE-EARTH ORE OCCURRENCE OF THE UKRAINIAN SHIELD (LITHO-STRATIGRAPHIC CRITERIА OF THE GENESIS AND LOCALIZATION OF ORE BODIES)

Abstract

The paper compares the Dibrovskoe uranium-thorium-rare-earth ore occurrence of the Ukrainian shield (northern Azov region) by a num-ber of criteria (structural-tectonic, formational, stratigraphic, geochronological, lithological, mineral-petrographic, geochemical) with similar well-known objects of the Ukrainian shield (Nikolo-Kozelskoye deposit, Severo-Tersyan ore occurrence, etc.).The objects are con-cluded to be genetically similar. These deposits and ore manifestations are localized in the formation rocks of ancient metamorphosed con-glomerates, gravelites and sandstones and belong to a single stratigraphic level – the base of the paleoproterozoic protoplatform cover. New mineralogical and geochemical data have been obtained confirming the initially sedimentary (alluvial) genesis of thorium-rare-earth concentrations of the Dibrovskoe ore occurrence. The genesis of uranium concentrations in the ores remains disputed – it is associated with the influence of both sedimentary syn-diagenetic and superimposed epigenetic, metamorphic, ultrametamorphic, metasomatic processes manifested in the ore occurrence, whose role in ore formation remains to be assessed. The main search criteria for the complex uranium-thorium-rare-earth mineralization of the Dibrovsky (Nikolo-Kozelsky) type were specified: the main local search criteria are the castle parts of the synclines and areas with an increased capacity of clastogenic pre-iron strains of the lower skelevatsky stratigraphic level. A favorable factor is the proximity of archean microcline monazite-containing granite massifs, which served as the area of weathering and the source of clastogenic material. A list of promising structures within the eastern part of the Ukrainian Shield has been outlined.

Keywords

• uranium
• thorium
• metallogeny
• early precambrian
• dibrovskoe ore occurrence