GEOLOGY, PETROLOGY AND URANIUM DISTRIBUTION IN GRANITIC MASSES OF WADIS FALIQ EL-SAHL AND FALIQ EL-WAAR, NORTH EASTERN DESERT, EGYPT

Faliq El-Sahl and Faliq El-Waar granitic plutons are located in the north Eastern Desert. The field
studies clarified that the younger granites are related to successive magmatic intrusions forming two main
granitic masses and pegmatite within both granites. Petrographically, the main rock types of each of the two
masses are monzogranites and syenogranites. Pegmatites could be classified into mineralized pegmatites
within the syenogranites and non-mineralized pegmatites which are distributed within the monzogranites.
The main fault trends cutting through the study area in decreasing order of predominance are NNWSSE,
NW-SE, NE-SW and NNE-SSW. The younger granites are dissected by four major sets of joints, in
decreasing order of abundance striking NW-SE, NE-SW, NNW-SSE and ENE-WSW.
Geochemically, the studied granites originate from peraluminous subalkaline magma considered as
post orogenic within plate granites, intruded in a crust of thickness between 22 km and 30 km; with Rb/Sr
ratios range from 0.1 to 1.0 during crystallization of monzogranites but Rb/Sr ratios range from 1.0 to
10.0 during crystallization of syenogranites. The geochemical ratios of the studied younger granites show
similarity to a great extent suggesting that these granites represent outcrops of one batholith and originate
by magmatic differentiation of the same magma.
The syenogranites could be considered as uraniferous granites (U 19-14 ppm, Th 31-26 ppm) originated
from highly fractionated U-rich magma. In monzogranites uranium exist only in zircon, sphene and apatite.
Uranium essentially concentrated during the magmatic stage in apatite and zircon. Both meteoric water and
hydrothermal solutions allowed to liberate U+6 and to be redepositing along microfractures supported by
increasing uranium content in the secondary hematite and fluorite.
Pegmatites show higher U-contents relative to both granite types with presence of uranophane mineral
within the syenogranites