Shear-zone hosted gold mineralization of the Arabian–Nubian Shield: devolatilization processes across the greenschist–amphibolite-facies transition

2018 ◽  
Vol 478 (1) ◽  
pp. 287-313 ◽  
Author(s):  
Tamer Abu-Alam ◽  
Mohamed Abd El Monsef ◽  
Eugene Grosch
Keyword(s):  
Shear Zone ◽  
Gold Mineralization ◽  
Amphibolite Facies ◽  
Nubian Shield ◽  
Arabian Nubian Shield ◽  
Facies Transition

scholarly journals Perspective of gold-bearing deposits in the ferruginous-siliceous formations of Egypt and Kursk Magnetic Anomaly

2019 ◽  
Vol 20 (2) ◽  
pp. 174-183
Author(s):  
Hani E. Sharafeldin ◽  
Alexander A. Vercheba
Keyword(s):  
Gold Mineralization ◽  
Hydrothermal Activity ◽  
Eastern Desert ◽  
Iron Silicate ◽  
Shear Cracks ◽  
Nubian Shield ◽  
Tectonic Dislocations ◽  
Silicate Deposits ◽  
Arabian Nubian Shield ◽  
Gold Bearing

Banded ferruginous-siliceous formations (FSF) are confined to the Precambrian basement of the Arabian-Nubian Shield within the central part of the Eastern Desert of Egypt. Gold mineralization is spatially associated with banded ferruginous quartzite, representing one of the most ancient manifestations of gold ore. The Precambrian rocks are combined into deposits complex of the Neoproterozoic Pan-African megacycle of the territory development. Banded iron-silicate rocks occur in sedimentary-volcanogenic rocks that were formed in the subduction trough zones, and are represented by metamorphosed ferruginous quartzites, jaspilites and schists. FSF show tectonic dislocations, shear cracks, and fracture cracks made by gold-quartz-sulphide mineralization. Promising for the identification of gold-bearing mineralization in the rocks of the FSF can be iron-silicate deposits with the occurrence of epigenetic hydrothermal activity as a result of activation of the submarine volcanism of the tholeiitic type.

DIVING DEEPER INTO THE PICURIS OROGEN: UPPER AMPHIBOLITE FACIES METAMORPHISM AND BRITTLE DEFORMATION ALONG THE PLOMO SHEAR ZONE

2020 ◽  
Author(s):  
Adrian E. Castro ◽  
◽  
Chloe Bonamici ◽  
Christopher G. Daniel ◽  
Danielle Shannon Sulthaus
Keyword(s):  
Shear Zone ◽  
Amphibolite Facies ◽  
Brittle Deformation ◽  
Facies Metamorphism

Genesis of gabbroic intrusions in the Arabian Shield, Saudi Arabia: mineralogical, geochemical and tectonic fingerprints of the Neoproterozoic arc magmatism

2021 ◽  
pp. 1-18
Author(s):  
Shehata Ali ◽  
Abdullah S. Alshammari
Keyword(s):  
Saudi Arabia ◽  
Fault System ◽  
Geochemical Data ◽  
Stability Field ◽  
Arabian Shield ◽  
Red Sea Rift ◽  
Nubian Shield ◽  
Najd Fault System ◽  
Garnet Stability Field ◽  
Arabian Nubian Shield

Abstract The Arabian Shield of Saudi Arabia represents part of the Arabian–Nubian Shield and forms an exposure of juvenile continental crust on the eastern side of the Red Sea rift. Gabbroic intrusions in Saudi Arabia constitute a significant part of the mafic magmatism in the Neoproterozoic Arabian Shield. This study records the first detailed geological, mineralogical and geochemical data for gabbroic intrusions located in the Gabal Samra and Gabal Abd areas of the Hail region in the Arabian Shield of Saudi Arabia. Geological field relations and investigations, supported by mineralogical and geochemical data, indicate that the gabbroic intrusions are generally unmetamorphosed and undeformed, and argue for their post-collisional emplacement. Their mineralogical and geochemical features reveal crystallization from hydrous, mainly tholeiitic, mafic magmas with arc-like signatures, which were probably inherited from the previous subduction event in the Arabian–Nubian Shield. The gabbroic rocks exhibit sub-chondritic Nb/U, Nb/Ta and Zr/Hf ratios, revealing depletion of their mantle source. Moreover, the high ratios of (Gd/Yb)N and (Dy/Yb)N indicate that their parental mafic melts were derived from a garnet-peridotite source with a garnet signature in the mantle residue. This implication suggests that the melting region was at a depth exceeding ∼70–80 km at the garnet stability field. They have geochemical characteristics similar to other post-collisional gabbros of the Arabian–Nubian Shield. Their origin could be explained by adiabatic decompression melting of depleted asthenosphere that interacted during ascent with metasomatized lithospheric mantle in an extensional regime, likely related to the activity of the Najd Fault System, at the end of the Pan-African Orogeny.

Geochemistry and P–T–t evolution of the Abu-Barqa Metamorphic Suite, SW Jordan, and implications for the tectonics of the northern Arabian–Nubian Shield

2013 ◽  
Vol 239 ◽  
pp. 56-78 ◽  
Author(s):  
Ghaleb H. Jarrar ◽  
Thomas Theye ◽  
Najel Yaseen ◽  
Martin Whitehouse ◽  
Victoria Pease ◽  
...  
Keyword(s):  
Nubian Shield ◽  
Arabian Nubian Shield
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