MINERALOGY AND GEOCHEMISTRY OF STREAM SEDIMENTS OF SOUTHEAST WADI GHADIR, SOUTH EASTERN DESERT, EGYPT

Southeast Wadi Ghadir area is located between latitudes 24◦ 47′ 00″ and 24◦ 49′ 00″ and longitudes 34◦ 58′ 18″ and 34◦ 59′ 30″. Geological and geochemical studies were carried out on the stream sediments and adjacent granites along some tributaries of Southeast Wadi Ghadir area, Southeastern Desert, Egypt. This investigation was carried out in order to identify the rock units with their stream sediments and to determine the concentration and distribution of trace elements granites with a view to elucidate the mineral potentials of the studied area.
Geological studies reveal the two rock types of granites, which are granodiorites and syenogranites. Granodiorites are composed of plagioclase, quartz, K-feldspar as essential felsic minerals. Biotite and hornblende are the essential mafic minerals. Apatite, zircon and opaques are accessory minerals. Syenogranites are composed of K-feldspar, quartz, plagioclase, biotite, as essential mineral constituents, while muscovite, zircon, allanite, apatite and opaques are accessories.
The analytical results reveal that the trace elements analyzed for granitiod rocks and stream sediments include; Cr, Ni, Cu, Zn, Zr, Rb, Y, Ba, Pb, Sr, Ga, V and Nb, which reveal that the stream sediments show higher average contents of most of the trace elements than the adjacent granitiod rocks except Ga which is not detected in the analyzed stream sediments samples.
Mineralogically, some important minerals were recorded in this study as; monazite, pseudo-autunite, goethite, hematite, pyrite, cinnabar, wulfenite, galena, natro-jarosite, titanite, and anatase.
Radiometrically, the syenogranites had eU more than twice Clark value; this indicates that the syenogranites were uraniferous and have been subjected to post-magmatic changes. Radiometric investigation of the studied stream sediments samples showed that the eU ranged from 5.0 ppm to 19 ppm and eTh ranges from 11 ppm to 92 ppm at the surface, while with depth the eU ranges from 6.0 ppm to 45.6 ppm and eTh ranges from 10 ppm to 52 ppm. The radioactivity increases with depth in all studied samples except sample number 2, indicating that uranium add to stream sediments from the adjacent granitic rocks.