Radioactivity of Phosphorites and Some Opinions on Their Genesis

Abstract In Albania there are discovered phosphorite mineralization of the Upper Cretaceous (Coniacian) and Middle Jurassic. The application of radioactive methods have had concrete results and have solved concrete problems (Dafa F., Serjani A., 1994): theoretical solving of the character of distribution of useful components U and P2O5; determination of the mutual correlations between U, P, F and Gamma intensity, discovering the coefficients for the main chemical and radio metrical constituents etc. The differences of the uranium content between Coniacian Phosphate Horizon and Middle Jurassic uranium-bearing mineralization can be explained by their differences in genetically aspect. The formation of phosphate-carbonate-siliceous horizon happened into the pelagic, deep sea, reduced environment of Ionian Trough, where the clastic, terrigenous matter is totally missing, and phosphate beds are very clean, constituted only by phosphate and calcite minerals. Middle Jurassic uranium-bearing phosphorites were formed in photic zone, in shallow water environment, on submarine mountains (high parts) of break in sedimentation. Phosphate mineralization is accompanied by high content of organic matter, dolomite, pyrite, quartz and some other detritus minerals. The high content of uranium can be explained due to above mentioned accompanied constituents and by the absorption during digenetic processes.