Radioelements and uranium migration in granites, El-Missikat Tunnels, Central Eastern Desert, Egypt

الملخص EN

Fracture-filling uranium mineralization, connected mainly to black and jasperoid silica veins, occupying shear and fracture zones, was detected in 1968-1969 at the northern margin of El- Missikat post-tectonic granite, Central Eastern Desert, Egypt.

Tunnels and excavations were executed, nearly at Wadi level, following these shear zones, in order to determine extensions of parts of the tunnels and evaluate their potentiality.

Excavation works revealed the existence of disseminated pitchblende, as well as its secondary association, in some drifts of the explored shear zones.

The granite along the shear zone is intensely altered.

The main alteration features are silicification, sericitization and kaolinization.

An extensive gamma-ray spectrometric survey was carried out on some of the mineralized parts.

The obtained data were statistically treated in order to outline the radiolithological features of the different rock units in the prospect area.

The original uranium content and uranium migration rate were calculated in order to identify the migration trends in the granite and its alteration products.

The study shows that there is a close relationship between the distribution of radioelements and lithology, in which the silica veins and silicified granites posses the highest radioelement contents.

The migration of uranium took place inward in the brecciated jasperoid silica, massive silica and silicified granite.

Meanwhile, the migration is outward in the case of pink (unaltered), kaolinized, and sericitized granites.

The results show that, the pink granite has the highest outward uranium migration rate (.148), followed by the sericitized granite (up to .123).

The kaolinized granite has the lowest outward 90 A.

Abu-Deif et al.

uranium migration (up to .67).

Meanwhile, both silica types the silicified granite and jasperoid silica show inward uranium migration rate reach up to 56 and 77, respectively.

These results reflect the similarity between uranium migration in the granitic rocks of El-Missikat prospect and the nearby El-Erediya prospect, located about 30 km to the south.