Gibbsite,
uranium and copper mineralizations, Um Bogma area, southwestern Sinai, Egypt.
Abdallah A. ABD ElMonem, Ibrahim E. ElAassy,
Omar. A. Hegab1, Ibrahim F. ElFayoumy1 and Nasser L. EIAgami
Nuclear Materials Authority, Cajro,1Geology Dept.,
Fac. Sciences, Mansoura Univ., Egypt |
Gibbsite, uranium and copper mineralization
are found in the Um Bogma area SW Sinai, predominantly in the lower part of Um Bogma
Formation and to a lesser extent in Abu Thora Formation. The epigenetic U and Cu
mineralization is localized in highly jointed and faulted ferruginous sandstone, shale and
gibbsite.
The anomalous U content (up to 5000 ppm) in some of the studied rock units is attributed
to the presence of the secondary Urn minerals carnotite, metazeunerite metatorbernite,
metauranocircite, zippeite and bassetite, in addition to the uraniferous xenotime,
churchite and aluminum phosphate minerals which are present particularly in the
ferruginous sandstone. Moreover, copper minerals were recorded associated with the
secondary uranium minerals including atacamite, paratacmite, langite, szomolonkite,
chalchanthite and turquoise.
The proposed model for the genesis of gibbsite uranium and copper minerals in the area
suggests that thermal ground waters rich in sulfate and halide ions as well as U, Zn, Cu,
Pb, F, Fe and Mn moving along fractured zones have precipitated these minerals when
favorable redox conditions were encountered.
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