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Nine samples were chemically characterized and radiometrically analyzed for determination of  234 U,  238 U,  235 U,  230 Th,  232 Th,  226 Ra and  40 K by γ-ray spectrometer Hyper Purity Germanium (HPGe detector).  238 U activity concentrations reach up to 79.78 Bq Kg -1 in the altered granites, 1714.11 and 2223.48 Bq Kg -1 in the episyenite and pegmatite. Average  234 U activity concentrations in the altered granite is 59.26 Bq Kg -1 , between 175.88-543.47 Bq Kg -1 and 48.19-1102.88 Bq Kg -1 in the episyenite and pegmatite, respectively.  232 Th activity concentrations vary between 14.16-1024.8 Bq Kg -1 in the episyenite, 11.46-240.27 in the pegmatite and reach up to 201.45 Bq Kg -1 in the altered granites.  40 K activity concentrations range between 4.42-9.15, 2.76-7.34 and 2.68-9.94 Bq Kg -1 in the altered granite, episyenite and pegmatite, respectively.  235 U activity concentration ranges between 3.74–2.56, 12.45-78.86 and 0.58-102.34 Bq Kg -1  in the altered granite, episyenite and pegmatite, respectively. The studied altered granite, episyenite and pegmatite samples have relatively higher values than recorded in the international standards with the exception of potassium which has lesser amounts. It is demonstrated that pH changes, oxidation-reduction conditions, mineralogical constituents, in addition to alteration processes in these variable granitic environments were the main factors controlling uranium mobilization according to valid processes. The difference in alteration processes and La/Y ratio clarified the presence of more than one event of uranium accumulation and/or leaching in these rocks as confirmed by the presence of uranium accumulation and uranium vacant occurrences. Also, the isotopic ratios of uranium as  238 U/ 235 U, 234 U/ 235 U,  234 U/  238 U,  226 Ra/  238 U, 226 Ra/  230 Th,  210 Pb/  226 Ra,  230 Th/  238 U,  230 Th/  234 U with major, trace and rare earth elements were also affected by physico-chemical conditions changes. The present study shows that the samples of episyenite and pegmatite have been affected by leaching-accumulation events in the period from (1 × 10 5  to ˃2 × 10 5 years).

Physico-chemical conditions controlling the radionuclides mobilisation in various granitic environments