Geology and Petrography of Uraniferous Bitumens in Permo-Carboniferous Sediments (Vrchlabí, Czech Republic)

Uraniferous bitumens found in black shales from the Permian rocks at Vrchlabí Krkonoše Piedmont Basin (Czech Republic) were described and characterized petrologically mineralogically. The sediments originated weathering products metasediments granitoids of Krkonoše–Jizera Orlice–Sněžník crystalline complexes. organic matter contained up to 4.8 wt.% uranium, as uraninite grains. Elements associated with uraninite, such Pb, Zr, Cu, As, may have accumulated epigenetic fluids layers rich during their late diagenesis. bitumen structures extremely heterogeneous, a feature attributed radiolytic effects uranium. Amorphous bitumens, alternating various forms nodular corroded types multiple generations, present. Low highly altered weak anisotropy recognized, together halo zones, reflectance 4.37%. zones differed size, brightness, reflectance, increasing edge center. Halos often revealed dark rims between inclusions clear originating probably result weaker alterations due presence other inorganic components. Uranium concentration was main factor controlling degree alteration. studied uraniferous are an excellent example multistage formation diverse evolution burial