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Abstract. U-Mo and Cu mineralization occurs in horizons as well as in veins in the Permian formations near Novoveskfi Huta. Ore mineralization is represented by uraninite, U-Ti oxides, coffinite, molybdenite, chalcopyrite, tennantite and pyrite. The isotopic composition of S and C displays a larger variability in the stratiform ores (d3% from -32.7 to +2.7 and 813C from -27.1 to -0.5%0). These data suggest mixing of meteoric solutions with fluids of volcanic origin and a complex history. There is a narrower range of d34S from -18.8 to -4.6 and 813C from -6.3 to -2.5%0 in quartz-carbonate veins with Cu mineralization suggesting a deep source of ore-bearing solutions. The Permian volcanics were a significant source of ore elements.Their contents of U, Mo, Cu and Y are from two to eight times higher than in sedimentary rocks. Accumulations of ore elements in the horizons were formed by the reduction and adsorption processes 240 + 30 Ma ago according to U-Pb isotopic dating. Due to Alpine tectonism, these low-grade ores (U < 0.1 wt%) were remobilized and higher-grade U-Mo ores (U> 0.1 wt%) were formed 130 ___ 20 Ma ago at temperatures ranging from 110 to 120 ~ C, according to fluid inclusions. Younger veins with Cu mineralization were formed 115 _+ 10 Ma according to the model age of Pb at temperatures ranging from 95 to 190~

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