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

The present paper sheds some light on the mineralogy and radioactivity of stream sediments in Wadi
Hangaliya, South Eastern Desert of Egypt. Therefore, eighteen stream sediments have been examined. The
wadi is surrounded by several rock units; metavolcanics, mafic-ultramafic rocks and younger granites. The
grain size analyses reveal that stream sediments are immature, about 33% and 28% of the sediments lie
in the very coarse sand and coarse sand fractions, respectively. About 72% of the sediments are poorly
sorted. It attains average heavy 5.82 and 2.33 %for both fine and very fine sand size fractions, respectively.
The recorded heavy minerals include opaques with an average content of 13.3% and 14.6% in the fine and
very fine sand fractions, respectively. The opaques are dominated by magnetite, ilmenite and hematite. The
non-opaques include zircon, rutile, staurolite, sillimanite, titanite, amphiboles, pyroxenes, epidotes, apatite,
garnet, barite and tourmaline. The preliminary estimation of visible gold content in sand fraction giving
an average of 1.135 g/t Au. Gold was recorded in 72% of the studied samples. Ground spectroscopic
measurements and aero-radiometric previous work of the hinterlands show weak radioactivity; increasing
slightly to the west portion of Wadi Hangaliya. The increase in radioactivity may be attributed to Gabal
Nugrus younger granite. The radioactive minerals include; monazite, metamict zircon and thorite.
In addition, the presence of 40K in the potash feldspars and micas of the light fraction. Thus, the weak
radioactivity of Wadi Hangaliya makes it suitable for gold extraction field industry.