Geology, Radioactivity and Uranium Potentialities of Some Pegmatite Bodies at Wadi Al Shayilah and West of Gabal Kherm El Asmar Area, North Eastern Desert, Egypt

Abstract

The area around Gabal (G.) Kherm El Asmar is occupied by metavolcanics, Dokhan volcanics as well as different types of younger granite pertaining to the Syenogranites and alkali feldspar granites. These rock types are intruded and traversed by numerous types of dyke swarms and dissected by many fault trends. The metavolcanics are mainly represented mainly by metabasalt, metabasaltic andesite and very rare metamorphosed pyroclastics. The Dokhan volcanics are represented by andesite, dacite as well as acidic and intermediate tuffs and agglomerates. Syenogranites in the area represents a part of G. Urf El Eeir which is coarse grained porphyritic pink granites while alkali feldspar granites represent part of G. Al Shayilah medium grained equigranular reddish pink granite cut and dissected by dyke swarms and traversed by different trends of shear zones. Late magmatic pneumatolytic and hydrothermal stages which products pegmatites, aplites and silica veins are frequently seen in both types of granites but are very spectacular in alkali feldspar granites where large pegmatites veins and pockets are spread in many parts of the intrusion. These pegmatites play a major role in the localization and potentialities of uranium in this sector of younger granites. Most of the radioactive anomalies are connected to the alkali feldspar granites where U and Th have a reasonable concentrated. In the zoned pegmatites, the uranium concentration is seen to be relatively high and reaches up to 250 ppm while the Th recorded 75 ppm. The relatively high uranium concentration provides the opportunities for the crystallization of uranium minerals in these pegmatites where both Uranophane and Kasolite are recorded in notable amounts giving the high U potentialities for these pegmatites.