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The examination of gamma-ray spectrometric data of the Missikat area was found to be useful in locating areas worth exploring for uranium occurrence. The statistical treatment of these data shows that the uranium threshold level is 13 ppm. Such a value represents indirectly the presence of uranium mineralization and identifies anomalous areas on the eU contour map in the northern border of the Missikat-Ria EI Gerra granitic plutons. This area should be of prime concern in uranium exploration of these plutons. The interpretation of the variation in the eU/eTh ratio with eU and eTh suggests that uranium redistribution has occurred within the Missikat-Ria El Gerra granitic plutons. Uranium may be reconcentrated in silicification, sericitization and kaolinization alterations which are geologically evident. eU, eTh and their ratio eU/eTh for the Missikat-Ria El Gerra granites exhibit a lognormal distribution which is in agreement with the general distribution of trace elements, whereas the K content tends towards a normal distribution. (C) 2001 Published by Elsevier Science Ltd.