Metal and fluid sources in a potential world-class gold deposit: El-Sid mine, Egypt

Helmy, Hassan M.; Zoheir, Basem

doi:10.1007/s00531-014-1094-6

Cited by 22 publications

(5 citation statements)

References 45 publications

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“…Two different types of pentlandite are observed, homogeneous and zoned (Figure e). Zoning in pentlandite reflects variation in Ni contents in the different growth zones (Helmy & Zoheir, ). In some samples, amoeboid crystals of pyrrhotite with internal granules of pentlandite are recorded (Figure f).…”

Section: Resultsmentioning

confidence: 99%

Mineralogy and chemical aspects of some ophiolitic metaultramafics, central Eastern Desert, Egypt: Evidences from chromites, sulphides and gangues

Abdel‐Karim

El-Shafei

2017

Geological Journal

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Handling editor: P. HorváthChromites and sulphides are the most common ore minerals in the ophiolitic metasomatized ultramafics (~790 Ma) of Um Halham, Fawakhir and Barramiya, central Eastern Desert, Egypt.These ultramafics exhibit variable degrees of alteration and metasomatism and include massive serpentinites (serpentinized peridotite and serpentinite), tremolite-talc rocks, talc-carbonate rocks, listwaenite-like rocks and typical listwaenite.The alteration of chromite to Cr-magnetite was accompanied by the formation of chloritic aureoles due to the release of Al and Mg from chromite. Textural and compositional features of the chromites suggest a greenschist up to lower amphibolite facies metamorphism (at 500-600°C), which is facial with the host ultramafics. The chromites exhibit a boninitic affinity and a forearc suprasubduction setting of the present ophiolite assemblages. The variability of chromite chemistry indicates a melt-rock reaction, together with the water-bearing melt which is necessary for crystallizing chromite. Pentlandite, pyrrhotite, arsenopyrite, gersdorffite and pyrite are the most common sulphide minerals. Gold occurs either as an invisible phase associated with gersdorffite, arsenopyrite, and As-rich pyrite or as native nuggets in listwaenites of Barramiya area. Gangue metasomatized phases associated with these ore minerals are identified as sericite, carbonate and chlorite. The investigated sericite ranges in composition from mariposite (>0.5% Cr) to fuchsite (>1% Cr), which indicates typical listwaenites. Five varieties of carbonate minerals are identified; magnesite, breunnerite, dolomite, calcite and ankerite.The CO 2 -rich fluids are released during progressive decarbonation reactions in carbonate-bearing metasediments, whereas Ni and As-rich fluids are attributed to nearby granitic intrusions affected on serpentinites and leached Ni and precious metals like gold forming As-Ni-rich fluids. These metasomatic fluids are thought to reflect a range of melts derived from a compositionally evolving source during subduction initiation in a forearc environment.

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Section: Resultsmentioning

confidence: 99%

Mineralogy and chemical aspects of some ophiolitic metaultramafics, central Eastern Desert, Egypt: Evidences from chromites, sulphides and gangues

Abdel‐Karim

El-Shafei

2017

Geological Journal

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“…Most of the gold mineralization in the central KS is therefore coeval with the late tectonic formation of the KSZ overprinting the KS. At Nubian shield-scale, ~600 My-old gold mineralization hosted by quartz veins and related to ductile-brittle transcurrent structures is mostly characterized as orogenic gold (e.g., Elsamani et al, 2001;Klemm et al, 2001;Botros, 2002Botros, , 2004Helmy et al, 2004;El Kazzaz, 2012;Osman, 2014;Helmy and Zoheir, 2015;Khalil et al, 2016;Fawzy, 2017;Zoheir et al, 2019aZoheir et al, , 2019bZoheir et al, , 2019c.…”

Section: Polyphase Gold Dominated By Syn-keraf Shear Zone Mineralization In the Gabgaba Gold Districtmentioning

confidence: 99%

“…1a, b) constitutes the main Neoproterozoic gold province worldwide (Johnson et al, 2017). ANS deposits are mostly classified as orogenic gold occurrences preferentially hosted by major shear zones (e.g., Elsamani et al, 2001;Botros, 2002Botros, , 2004Helmy et al, 2004;El Kazzaz, 2012;Osman, 2014;Helmy and Zoheir, 2015;Khalil et al, 2016;Fawzy, 2017;Zoheir et al, 2019aZoheir et al, , 2019bZoheir et al, , 2019c, including the Keraf shear zone (KSZ) (Johnson et al, 2017). The KSZ is mapped in northeastern Sudan and southeastern Egypt, and overprints the ~500 km-long, ~70 kmwide, north-striking ophiolite-decorated Keraf suture (KS) which is rooted deep into the lithosphere (Almond and Ahmed, 1987;Abdelrahman, 1993;Abdelsalam et al, 1995;Abdelsalam and Stern, 1996a;Ahmed Suliman, 2000).…”

Section: Introductionmentioning

confidence: 99%

Tectonic record and gold mineralization in the central part of the Neoproterozoic Keraf suture, Gabgaba district, NE Sudan

Perret

Feneyrol²,

Eglinger

et al. 2021

Journal of African Earth Sciences

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The central Keraf suture recorded complex lithospheric-scale deformation associated with the formation of the Neoproterozoic Arabian-Nubian shield and hosts the WG03, Central Zone and UTM gold deposits, Gabgaba district, northeastern Sudan.This study aims at (i) unravelling the tectonic history recorded by the central Keraf suture and (ii) interpreting the spatial and genetic relationships between structural setting and gold mineralization. To this end, we coupled field petrographic observations and structural measurements made along a 50 km-long geological cross-section through the Gabgaba district with macroscopic and microscopic description of mineralized structures.The structural setting of the central Keraf suture is dominated by progressive deformation, from ductile D1a Keraf thrusting to ductile-brittle D1b sinistral shearing in a prolonged northwest-orientated convergence regime. A first mineralization event, leading to a minor gold endowment, relates to magmatic accretion pre-dating D1a Keraf suturing. The second gold episode is characterized by ore veining as a response to progressive late collisional D1b Keraf strike-slip shearing and may be classified as orogenic gold. Most of the gold budget of the Gabgaba district formed at this stage.In summary, the central Keraf suture exemplifies that the Arabian-Nubian shield contains significant polyphase gold mineralization along lithospheric-scale structures. These structures may record a complex tectonic evolution from magmatic accretion to collision, with a strong structural control on gold endowment.

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“…In this area, recent studies have shown the impact of carbonate alteration of ophiolithic ores; under hydrothermal conditions the remobilization of gold and sulfur caused the formation of gold deposit (Boskabadi et al, 2017). These hydrothermal alterations may explain not only the formation of these gold deposits but also its association to other base metals and calcareous mineralization (Helmy and Zoheir, 2015;Abdelnasser and Kumral, 2016).…”

Section: Introductionmentioning

confidence: 99%

Gold and Base Metals Associated with Uranium Mineralization in Some Lower Carboniferous Rock Units in the Wadi Abu El Mogheirat Area, Southwestern Sinai, Egypt

Sallam

Alshami

Abbas

et al. 2021

Acta Geologica Sinica (Eng)

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The Lower Carboniferous sediments at Wadi Abu El Mogheirat consist of four stratigraphic formations, from base upwards: Um Bogma, El Hashash, Magharet El Maiah and Abu Zarab formations. The most-concentrated radioactive anomalies at Wadi Abu El Mogheirat are in the middle member of the Um Bogma Formation. The gibbsitic marl in this formation shows the highest uranium contents (around 710 ppm). Gibbsitic marl and black gibbsite of the middle Um Bogma Formation show higher enrichment in Co, Cu, Mn, Ni, Pb, Zn, U, V, Ce and Th. Black gibbsite contains the highest total rare earth elements concentration, especially in terms of LREEs, while gibbsitic marl contains the highest content of HREEs. Anomalous contents of gold at Wadi Abu El Mogheirat are recorded for the first time in the gibbsitic marl (content: 10.4 ppm), black gibbsite (2.8 ppm) of the middle member of the Um Bogma Formation and in the siltstones of the El Hashash Formation (0.6 ppm). Gibbsitic marl shows the presence of uranothorite, celestite, zircon, atacamite, barite, xenotime and rutile. These characteristic demonstrate that the middle member of the Um Bogma Formation constitutes a potential source for gold. This conclusion is reinforced by the potential to exploit other metals such as Co, Cu, Mn, Ni, Pb, Zn, U, V, Th and Ce as by-products.

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Metal and fluid sources in a potential world-class gold deposit: El-Sid mine, Egypt

Cited by 22 publications

References 45 publications

Mineralogy and chemical aspects of some ophiolitic metaultramafics, central Eastern Desert, Egypt: Evidences from chromites, sulphides and gangues

Mineralogy and chemical aspects of some ophiolitic metaultramafics, central Eastern Desert, Egypt: Evidences from chromites, sulphides and gangues

Tectonic record and gold mineralization in the central part of the Neoproterozoic Keraf suture, Gabgaba district, NE Sudan

Gold and Base Metals Associated with Uranium Mineralization in Some Lower Carboniferous Rock Units in the Wadi Abu El Mogheirat Area, Southwestern Sinai, Egypt

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