Sedimentological Society of Egypt

AN ORIENTATION SURVEY FOR URANIUM AND OTHER ORE ELEMENTS IN STREAM SEDIMENTS OF UMM SHALMAN CATCHMENT AREA, SOUTH EASTERN DESERT, EGYPT
ABDALLAH A. ABDEL-MONEM¹, SAMIR A. AWAD², HUSSEIN A. HUSSEIN¹, HAMDY M. ABDALLA¹ AND SAMY M. EL-BOUHY¹

¹Nuclear Materials Authority, Cairo, Egypt. ²Geo/ogy Dept., Fac. Sci., Ain Shams Univ., Cairo, Egypt.

Lithochemical survey was carried out in stream sediments of Umm Shalman area, South Eastern Desert, Egypt. The results were treated by applying multi-variate statistics to both the geochemical and heavy minerals data to interpret the mode of occurrence and type of geochemical dispersion of the ore elements.

The trace elements behavior was examined using probability graphs in order to determine the geochemical distribution parameters (background and threshold values) of the ore elements. Both Ni and Cr exhibit normal distribution pattern along two intersecting straight lines indicating normal distribution bimodal populations. All the other trace elements (Li, Be, Rb, Sr, Ba, Ga, Y, Zr, Nb, Th, U, Zn, Cu, Pb, Co, V and F) exhibit distribution along two straight lines separated by a sigmoidal segment indicating that the data represent two mixed geochemical populations where the lower value lines represent the backgrounds and the higher value lines represent the anomalous populations.

Application of factor analysis indicated that the variability in heavy minerals could be explained by 3 factors with the most important being due to accumulation of resistant minerals such as zircon, monazite, apatite, fluorite, xenotime, thorite and muscovite. These have been correlated with the association of the elements Y, Zr, Th, U and F, which is considered to represent uraniferous accessory minerals shed from acidic igneous rocks and granitioid lithologies. The Factor-2 mix is due to the accumulation of Fe-minerals magnetite, ilmenite, hematite as well as the rock forming minerals pyroxenes, amphiboles, biotite, chlorite, epidote and sphene, which has been also correlated to the association of the elements Sr, Ni, Co, Cr, Pb and V. These are strongly related to the distribution of basic igneous rocks and secondary Fe-enrichment. The Factor-3 mix is due to accumulation of staurolite, carbonates, garnet and topaz and attributed to high-grade schists and calc-silicates, which has been correlated to the association of Li, Be, Rb, Ba, Ca, Nb, Cu and Zn tentatively considered to represent potential Cu-Zn mineralization in the area.