URANIUM MINERALIZATION HOSTED BY THE PALEOZOIC SANDSTONES AT SOUTHWEST SINAI, EGYPT

The uranium mineralization hosted by the Paleozoic sandstones is one of two types: The first is the
syngenetic continental/littoral paleoplacers (refractory Th-U bearing minerals) which were detritus from
far distant source rocks. These minerals are mainly uranothorite, thorite, zircon, cheralite, chevickinite,
davidite, xenotime, and monazite. Meander loops and channels with deep scours appear to be the most
favourable sites for this mineralization. The second is the tectonic-lithologic sandstone-type uranium
deposits being epigenetic U-enrichment within the sandstones along the permeable fault zones. It contains
saleeite, sodium-meta-autunite, threadgoldite and uvanite in addition to REE-bearing iron and aluminium
phosphate minerals; vivianite, goyazite, wavellite, florencite and plumbogummite. The studied Paleozoic
sandstones are enriched in P2O5, Al2O3, Fe2O3, TiO2, Zr, Y, Sr, Ni, Cr, Zn, Pb, Ba, V, U and Th relative to
the Upper Continental Crust (UCC). This enrichment may be attributed to the high content of zircon, iron
oxyhydroxides, phosphate minerals (either uranium or aluminium phosphates) and iron titanium detrital
minerals. Ga, W, Sn and REE show considerable concentrations in the radioactive Cambro-Ordovician
sandstones at Gabal Hemeyir and Ras Millan areas.
The tectolithologic sandstone-type uranium deposits is occurring in significant quantities in the
ferruginous sandstones of El Adedia Formation at both Gabal Hemeyir and south Wadi El Sahu localities
as well as its equivalent sandstones of Araba Formation at Ras Millan area. These promising deposits
represent important U-resources in southwest Sinai. The tectolithologic U–type deposits are stacked as
discordant bodies through more than one stratigraphic horizon at Gabal Hemeyir, south Wadi El Sahu
and Ras Millan areas. The importance of these localities for uranium mineralization is related to possible
presence of reduced environment along these fault zones.