Mineral chemistry of some gabbroic rocks of the Central Eastern desert, Egypt

Genesis and Tectonic Implications of the Kabr El‐Bonaya Ultramafic Rocks, Sinai Peninsula, Egypt: Constraints from Mineralogical and Geochemical Characteristics

“…5c). The Fo contents of the analyzed olivine from the studied peridotite conforms well to those from oceanic supra-subduction zone peridotites (Arai, 1994) and those from the Egyptian unmetamorphosed non-ophiolitic mafic-ultramafic intrusions (Fo < 83; e.g., Abdel Kader and Hafez, 1985;Ghoneim, 1989;Khudeir, 1995;Moussa, 2002;Helmy and El Mahallawi, 2003;Farahat and Helmy, 2006;Azer and El-Gharbawy, 2011;Abd El-Rahman et al, 2012;Khedr and Arai, 2016).…”

The Neoproterozoic layered mafic–ultramafic intrusion of Gabal Imleih, south Sinai, Egypt: Implications of post-collisional magmatism in the north Arabian–Nubian Shield

“…MgO contents of clinopyroxenes decrease from peridotite (16.54-17.71 wt.%) to pyroxenite (16.16-16.40 wt.%) and cumulus gabbro (16.00-15.83 wt.%) which is consistent with the crystallization from the same magma undergoing fractionation. The pyroxenes of the studied layered intrusion have almost the same chemical composition as those recorded from unmetamorphosed younger Egyptian gabbros (Ghoneim, 1989;Basta et al, 1996;Basta, 1998;Abdel-Karim, 2002). On SiO 2 -Al 2 O 3 diagram ( Fig.…”

“…Fo contents in the analyzed olivines range from 0.81 to 0.83 and are lower than those of the primary olivines of the peridotite of the ophiolites in the Eastern Desert of Egypt (0.91 to 0.93 and 0.89 to 0.96) (Khudeir, 1995a;Khalil and Azer, 2007, respectively). The analyzed olivine has Fo contents similar to those of the younger mafic-ultramafic intrusions in the Eastern Desert of Egypt (Khudeir, 1995b;Abdel Kader and Hafez, 1985;Ghoneim, 1989;Helmy and El Mahallawi, 2003;Farahat and Helmy, 2006).…”

Origin and evolution of Neoproterozoic metaophiolitic mantle rocks from the eastern Desert of Egypt: Implications for tectonic and metamorphic events in the Arabian-Nubian Shield

“…Olivine relicts show a compositional range (Fo 91-94 ; Table III) like that of primary olivine of mantle rocks in the Egyptian Eastern Desert ophiolites (Fo 89-96 ) (Abdel-Karim et al, 2018;Khalil and Azer, 2007;Khedr and Arai, 2013;Moussa et al, 2021Moussa et al, , 2022Obeid et al, 2016). The high Fo contents are akin to those in the ANS ophiolitic ultramafic rocks and fore-arc peridotites (Abuamarah et al, 2020;Stern et al, 2004) but are clearly distinct from those in olivine from the non-ophiolitic mafic-ultramafic intrusions in the ANS (Fo= 77.5-86.5: Abd El-Rahman et al, 2012;Azer and El-Gharbawy, 2011;Azer et al, 2016Azer et al, , 2017Farahat and Helmy, 2006;Gahlan et al, 2023;Ghoneim, 1989;Helmy and El Mahallawi, 2003). Their Fo and NiO contents fall within the range of the SSZ ophiolitic serpentinites of the EDE and overlap those of the olivine mantle array (Fig.…”