New Data on Minerals. 2011. Vol. 46 71 SIMPLE URANIUM OXIDES, HYDROXIDES U4+ + U6+, SIMPLE AND COMPLEX URANYL HYDROXIDES IN ORES Andrey A. Chernikov Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow,
[email protected],
[email protected] The review of published and new own data of simple uranium oxides revealed that the formation of five simple oxides is probable: nasturan, sooty pitchblende, uraninite, uranothorianite, and cerianite. Among simple oxides, nasturan, sooty pitchblende, and uraninite are the most abundant in ores varied in genesis and mineralogy. Uranothorianite or thorium uraninite (aldanite) is occasional in the ores, while cerianite is believed in U-P deposits of Northern Kazakhstan. Hydrated nasturan is the most abundant among three uranium (IV+VI) hydroxides in uranium ores. Insignificant ianthinite was found in few deposits, whereas cleusonite was indentified only in one deposit. Simple uranyl hydroxides, schoepite, metaschoepite, and paraschoepite, are widespread in the oxidized ores of the near-surface part of the Schinkolobwe deposit. They are less frequent at the deeper levels and other deposits. Studtite and metastudtite are of insignificant industrial importance, but are of great inter- est to establish genesis of mineral assemblages in which they are observed, because they are typical of strongly oxidized conditions of formation of mineral assemblages and ores. The X-ray amorphous urhite associated with hydrated nasturan and the X-ray amorphous hydrated matter containing ferric iron and U6+ described for the first time at the Lastochka deposit, Khabarovsk krai, Russia are sufficiently abundant uranyl hydroxides in the oxidized uranium ores. Significant complex uranyl hydroxides with interlayer K, Na, Ca, Ba, Cu, Pb, and Bi were found basically at a few deposits: Schinkolobwe, Margnac, Wölsendorf, Sernyi, and Tulukuevo, and are less frequent at the other deposits, where quite large monomineralic segregations of nasturan and crystals of uraninite were identified.