MINERALOGY AND RADIOACTIVITY STUDIES OF WADI YOIDER STREAM SEDIMENTS, SOUTH EASTERN DESERT, EGYPT

Wadi Yoider area is located in the South Eastern Desert of Egypt, covering an area of about 150km2. It is covered by basement rocks dissected by Wadi Yoider as a main wadi with several tributaries. The rock types cropping out at Wadi Yoider area comprise, from the oldest to youngest, metavolcanics, younger gabbros, alkali feldspar granites, muscovite granites, biotite granites, monzogranites, and wadi deposits (quaternary sediments) filling the streams of the studied area. The results of the sedimentological statistical parameters are graphic mean (Mz) indicate that, they range from 0.04 to 1.8 with average 0.85, inclusive graphic standard deviation (σI) ranging from 0.88 to 1.8 with an average 1.2, inclusive graphic skewness (SkI) ranging from 0.03 to 0.33 with an average 0.2, and inclusive graphic kurtosis (Kg) ranging from 0.68 to 2.05 with an average 1.4. These samples are characterized by fine skewed, neer skewed, coarse skewed, platykurtic and mesokurtic. All these features indicate of a turrstile. Gravity and magnetic separation techniques in addition to microscopic examination for the studied stream sediment samples were applied to identify the heavy minerals in these sediments. These minerals are represented by magnetite, ilmenite, hematite, rutile, leucoxene, garnet, titanite, zircon, and samarskite. The average concentrations of U and Th in the stream sediments of Wadi Yoider are 20.2ppm and 42.2ppm, which are higher than the clarke values for earth crust