MINERALOGICAL AND GEOCHEMICAL FEATURES OF THE MOLYBDENUM-URANIUM DEPOSITS IN THE KATTASAI-ALATANGA ORE FIELD (UZBEKISTAN)

The deposits of the Kattasai-Alatan'ga ore field are typical for the M o-U ore type. They are widespread in the territory of the former USSR. At the deposits of this type, economic Sn, Mo-U, and complex Sn-Mo-U mineralizations are related to a single hydrothermal process. Due to a near-surface telescoping, they combine several stages of the U minera lization: (1) albiteite, (2) greisen with cassiterite, (3) beresite, ( 4) quartz-sulfide-carbonate, (5) quartz-barite-fluorite, (6) pitchblen de-sulfide, and (7) postore quartz-barite-fluorite-calcite. The author s specially studied pitchblende and Fe-molybdenite, typical minerals o f the Mo-U deposits. It was established that geochemical barriers play an important role in the deposition of various paragenetic mineral as semblages. Inversion-cyclic changes of the parameters of hydrothermal solutions during the mineral formation were suggested. A mineralogical -geochemical model, describing the main factors of the formation of th e Mo-U deposits, was proposed.