الفهرس 
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Abstract
Nuweibi area is located in the Central Eastern Desert, 30 km north of Marsa Alam
and about 33 km west of the Red Sea coast. It lies between latitudes 25○ 10\ 30\\ and 25○
15\ 15\\ N and longitudes 34○ 29\ 00\\ and 34○ 38\ 29\\ E, covering an area of about 135
km2. It is mainly covered by metasediments, serpentinites, metagabbros, grey granites,
albite granites, post and pre-albite granite dykes.
The Nuweibi albite granite is one of 14 Known Sn-Ta-Nb bearing granitoids (
Hawashis, Umm Naggat, Umm Samra, Nuweibi, Ineiga, Humer Waggat, Igla, Zabara,
Muweilha, Nugrus, El Gharabiya, Nikeiba and Humr Akarem) in the Eastern Desert of
Egypt.
Nuweibi area is drained by two main wadis, the first one is Wadi El-Nabi located at
the north while the second is Wadi El-Nuweibi at the south. The Nuweibi albite granite
was divided by N-S fault into two unequal parts, Eastern (with dimension of about
950m*400m with elevation of about 300m) and Western parts (with dimension of about
1.37km*1.33km with elevation of about 450m). The present study concerned with the
Eastern part and the stream sediments of both wadis. The area has been studied
geologically, minerlogically, chemically, geophysically and stream sediment analysis.
Structurally, from Structural Lineament Statistical Analysis there are three sets of
faults controlling the regional framework of the study area. They are E-W, NNW-SSE
and NNE-SSW respectively. They are controlling the distribution of albite granite, mafic
and intermediate dykes. The area of study characterized by different rock unites
represented by serpentinites, metasediments (schist), metagabbros, grey granite, prealbite
granite dykes, albite granite and post-albite granite dykes.
The grain size analysis of both wadis shows that, the sediments of Wadi El-Nabi are a
mixture of gravelly sand and sandy gravel while Wadi El-Nuweibi sediments is gravelly
sand. The statistical sedimentological parameters shows that, the sediments of Wadi El-
Nabi are very coarse and coarse sand size, very poorly sorted, coarse skewed and
platykurtic, while the sediments of Wadi El-Nuweibi are very coarse and coarse sand
size, poorly sorted, coarse skewed and mesokurtic. Consequently, the sediments of Wadi
El-Nabi and Wadi El-Nuweibi displays river characters that deposits in fluviatile
environment.
Mineralogically, The distribution of total heavy fraction in Wadi El-Nabi shows that,
the fine sand size display relatively high content of the total heavy minerals. The total
heavy minerals in Wadi El-Nabi also does not show regular trend along the stream, on
contrast the distribution of total heavy minerals in Wadi El-Nuweibi are slightly enriched
in upstream than downstream. The obtained data reflected that, the spot surface samples
attain total heavy minerals greater than that in trench samples. The concentration of
magnetite in Wadi El-Nuweibi and its spot surface samples are greater than that in Wadi
El-Nabi and its spot surface samples. the average magnetite content in Wadi El-Nabi is
nearly a half of its content in Wadi El-Nuweibi in the three fraction sizes.
The heavy minerals were identified and described by microscopic examination. The
heavy minerals recorded in the area are: The opaque minerals represented by magnetite,
ilmenite, hematite, goethite, chromite, leucoxene, tantalite-columbite, molybdinite,
pyrolusite and the non opaque minerals represented by zircon, rutile, epidote, garnet,
cassiterite, monazite, fluorite and sphene beside other minerals such as pyrite, barite,
atacamite, apatite, autunite, allanite, REE bearing biotite and Less stable minerals such as
pyroxenes and amphibole minerals group.
Geochemically, the studied metagabbros are mainly calc-alkaline to slightly tholeiitic,
originated in island-arc tectonic environment. The albite granite is mostly calc-alkaline, Itype
and originated in within plate to post orogenic tectonic setting.
the studied stream sediment samples plot in the greywacke field, in sodic field with
high concentration of (Fe2O3 + MgO). According to the two discrimination functions
diagram, the source of the studied stream sediments are mafic igneous provenance and
intermediate igneous provenance.
Geophysically, The Nuweibi granite is discriminated by their high radioactivity
and the superimposed contour lines have two specific trends (NNE-SSW and NNWSSE).
They controlling by E-W regional structural trend. The field radiometric survey
revealed that; the potassium show the same concentration in both wadis either inside or
outside the borehole. Uranium slightly highly concentrated in Wadi El-Nabi than that in
Wadi El-Nuweibi, on the other hand thorium show remarked concentration in Wadi ElNuweibi
than that in Wadi El-Nabi either inside or outside the borehole. The laboratory
analysis do not show any remarkable variation between Wadi El-Nabi and Wadi El-
Nuweibi either inside or outside the borehole.