A. General Statements:
The copper deposits were encountered at several areas in Eastern Desert, such as Abu Swayel, Hamash, Um Samuki, Gabbro Akarm and
El Geneina El Gharbia.
1. Abu Swayel copper:
The most of the copper-Nickel occurrences known in Egypt were discovered and exploited by ancient Egyptians thousands of years ago in the location called Abu Swayel. It should be noted that Abu Swayel also has been spelled Abu Sweil. The Abu Swayel area occurrence in south eastern desert lies some 185 km south east of Aswan, and is located at latitudes 22º 47' N and longitude 33º38' E (Fig.1) show the location of studied area in Egypt , (Fig.2) show the location of studied area in Wadi Allaqi, (Fig.3) show the studied area (Abu Swayel). Abu Swayel is considered one of the most important copper occurrences in the Egyptian basement rocks. In 1902, a mining company explored and evaluated the copper occurrences there and since then many other geologic groups and companies have investigated in area. At the north eastern corner of Abu Swayel there are some relatively high hills, and at the south western corner there is a low country in prevailing, while in between lies a moderately hilly country. The only elevation point established by the survey Dept. in the area is that of Urf Um Shilman with an elevation of 389m above sea level.
According to the geosynclinal model, the oldest rocks at the greater Abu Swayel area are represented by thick geosynclinal flysch sediments which have been invaded by main geosynclinal volcanics in thick sheets of varied composition. The geosynclinal sediments and volcanics have been subjected by folding, and metamorphism within amphibolite facies.
The Greater Abu Swayel area is covered by basement rocks cut by Wadis filled with Quaternary alluvium. The basement rocks are ranging in age from the Precambrian to the cretaceous. Some minor igneous bodies may be even younger than the proved granite bodies’ of late Cretaceous age.
The earliest basement rocks are represented by geosynclinal sediments and volcanics eventually metamorphosed to give rise to many types of metamorphic rocks. These were intruded by various types of granites represented by plagioclase granite, graphic microgranite, whitish biotite granite, pink biotite granite, yellow muscovite granite and red muscovite granite. Fractures produced during and after the emplacement of granites.
Granites were occupied by dykes and veins of variable sequence and composition. Later tectonic events extending through the Phanerozoic produced other fracture systems which have been occasionally used as channels for igneous activity. The wadis are filled with gravels and sands which are generally formed by the weathering of the previously mentioned basement rocks.
2. Other occurrences:
· El Geneina copper occurrence:
A gossan with copper and nickel secondary minerals was discovered in 1973 during a geochemical exploration program undertaken by the Aswan Mineral Survey Project. Detailed study of the area, including some shallow diamond core drilling, showed that it is an occurrence with no economic potential (Garson and Fredrickson 1975).
Malachite [Cu2CO3 (OH)2], and Garnierite [(Ni, Mg)3 Si2O8 (OH)4] – stained gossans are associated with thrust slices of mafic- ultramafic rocks that include peridotite, pyroxenite and gabbros. Fresh ore minerals are represented mainly by Pyrite FeS2, Pyrrhotite [Fe1-xS], Chalcopyrite (CuFeS2) and Pentlandite (Fe, Ni)9 S8. (Fig.4)
· Gabbro Akarem copper:
This locality (Latitude 24o & Longitude 34o 17') was first discovered during reconnaissance geochemical prospecting in March 1972 in a gabbro peridotite complex located 130 km east of Aswan and 130 km west of Bernice (5 km south of Wadi Kharit and 20 km South-East of Gebel Homr Akarem. So, this locality has been given the name of Gabbro Akarem by Victor A.Bugrov and I.M. Shalaby. These rocks were found with traces of Cu-Ni sulphide mineralization and form a magmatic belt extending 10 km in ENE- WSW direction with a width of from 1 up to 3 km. This belt is differentiated into gabbro and peridotitic types (gabbro, olivine – gabbro, gabbro – norite, pyroxenite and peridotites) and is cut a cross by a system of diabase and gabbro-diabase dykes. In the fresh gabbroidal rock it is possible to find disseminated sulphides, i.e.
1. Pyrrhotite [Fe1-xS] softer than pyrite FeS2 (predominant) and
2. Chalcopyrite (CuFeS2) like gold in colour and
3. In polished section pentlandite [(Fe, Ni)9S8 associated with pyrrhotite] and cubanite (CuFe3S3) were identified. (Fig.4)
Also there are four zones of gossans were discovered during reconnaissance geochemical studies in the area (Fig.5), the distance between the western and eastern zones being about 7 km. The gossans are generally reddish – yellow to dark brownish –red in colour, light in weight and with cellular texture, they are typical of the oxidation of post massive sulphides (Fig.6).
In the host rock around the gossans there are secondary copper-nickel minerals with associated "copper-green" stains including:
2. Chrysocolla [ CuH2(Si2O5)(OH)4]
3. Turquoise [ CuAl6(PO4)4(OH)3.5 H2O] and
4. Garnierite [(Ni, Mg)3 Si2O8 (OH)4]. (Fig.4)
Gabbro Akarem is a small mafic_ ultramafic complex composed of two small bodies lying midway between Aswan and Berenice. According to Carter (1975) and Carter et al (1978), and personal communications with A.A.A.Hussein, the complex consists of two separate bodies which are steeply dipping dike-like intrusions, with inward dipping contacts against metasediments.
The main bulk of the complex is composed of noritic rocks, intruded by pipe-like bodies of peridotites in two generations, the later of which is mineralized with Cu-Ni sulphide minerals.
Gabbro Akarem was emplaced in association with a deep-seated transverse tectonic structure trending east-northeast. It is therefore suggested that, like most of the layered mafic- ultramafic intrusions in the world (Eckstrand 1984), Gabbro Akarem was formed from a mafic magma, mantle – derived in most cases, which was emplaced quiescently in multiple phases at higher crustal levels in a tensional rift environment.
B. Climate and Topography of Abu Swayel area:
The area under consideration lies in an arid-semiarid region where rainfall is rare and the scarcity of this rainfall coupled with the intense heat comprise obstacles to plant life in the area and that is why vegetation is scarce.
The area is characterized by some relatively high hills, and a low country in prevailing at the south western corner, while in between lies a moderately hilly country.
The only elevation point in the area is that of Urf Um Shilman with an elevation of 389m above sea level.
Topographically, the area have been dissected by three main wades (Haimur, Abu Swayel, and Mereikha) which are tectonically controlled and possessing a direction roughly NE-SW. Fig(1) Fig(2):The land sat image of Wadi Allaqi shows the studied area (Abu Swayel) Fig(3)
B. Previous work:
Several studies have been done to clarified, the geosynclinal relationships between the different rock types, geosynclinal parameters to estimate the copper deposits such as:
Abd El-Naby, H., and Frisch, W., (1999). Studied the Metamorphic Sole of Wadi Haimur-Abu Swayel Ophiolite: Implications on late Proterozoic accretion and stated that the metamorphic sole of Wadi Haimur-Abu Swayel ophiolitic rocks are formed of amphibolites, metagabbros, hornblendites, marbles and altered ultramafic rocks.
Bassyouni (1973) prepared the geological and structural map of Abu Swayel and it’s used as the basic reference for the present study (Fig.7)
Bassyouni (1973) stated that the oldest sedimentary rock unit in Abu Swayel region is marble, which is followed by hornblende schist, biotite schist, quartzo-feldspathic gneiss, serpentinite, amphibolite, andesite and dacite and ending with cross cutting granitoid rock varieties and their related dikes and veins.
Bassyouni and previous authors (1973), considered the shear zones and faults as the only structural elements controlling the localization of copper-nickel mineralization. However, this was proven by the mining and drilling there.
El Shazly, E.M., Bassyouni, F.A., and Abd El Khalek, M.L, (1975). Carried out the extention of the geological mapping and investigation of the Abu Swayel area.
DEMAG of West Germany (1963), studied the economic – geological and preliminary mining and the Core drilling by EGSMA.
There field seasons spent by EGSMA (1957 – 59), during which the prospect and its vicinity were studied. Apparently a detailed map was prepared but is not available.
El Ghawaby, M.A., studied the Role of Structural Deformation in controlling copper occurrences in the Abu Swayel Region and stated that the Abu Swayel region has been subjected to numerous stages of structural deformation and the zones of mineralization are primarily associated with metamorphosed amphibolitic rocks at the anticlinal crests and synclinal troughs.
El Shatoury, H.M., (1980) stated that the third tectonic phase was epeirogenic in character and resulted in the formation of red and yellow muscovite granites. This type of intrusive is subvolcanic in character and can be termed shallow postkinematic.
Farag, I.A.M., El Shazly, E.M., and Bassyouni, F.A., (1965) carried out the extention of the geological mapping and investigation of the Greater Abu Swayel area.
United Nations (1972), Airborne and ground electromagnetic surveys.
Ustav Pro Vyzkum Rud of (Czechoslovakia) (1958) used Magnetic, electrical and radiometric measurements.
Victor A.Bugrov and I.M Shalaby (1973) discovered and studied of Cu-Ni sulphide mineralization in Gabbro-peridotitic rocks in Eastern desert of Egypt.
C. Location and Accessibility:
The area under investigation is a part of the exposed Arabian-Nubian basement rocks in the South Eastern Desert of Egypt (Fig.1).
The area of study is lies some 185 km south east of Aswan and is delineated between Latitude 22o47'N and Longitude 33o38E.
The accessible from Aswan to Abu Swayel area is:
Aswan – Wadi Um Hibal – Um Ashira – Wadi Haimur and finally Abu Swayel mine. Asphaltic road.
A. Aim and Scope of the present work:
The main purposes of this study are:
- To study the copper-nickel deposits and mineralization in the Abu Swayel area.
- To clarify the geological setting and field relationships of the different lithological units encountered in this investigated area.
- To study the petrographical characteristics of these rocks under microscope and determine their essential mineral compositions and textures.
- To reveal the geochemical and petrochemical characteristics of these rocks.
- Finally to define the tectonic setting and petrogenesis of the rock units in the study area.