Geochemistry and Petrogenesis of the Neoproterozoic Granitoids in the Central Eastern Desert, Egypt

El-Sayed, Mohamed M.; Mohamed, F.H.; Furnes, Harald; Kanisawa, Satoshi

doi:10.1078/0009-2819-00010

Cited by 39 publications

(16 citation statements)

References 65 publications

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“…2a). It has been recognized as an A-type granite by Abdel-Rahman and El-Kibbi (2001) and El-Sayed et al (2002). Its contact is outward dipping, steplike in detail and there are lowdipping apophyses extending out into the wallrocks.…”

Section: El Sibai Granite and El Dabbah Granodioritementioning

confidence: 98%

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El Sibai gneissic complex, Central Eastern Desert, Egypt: Folded nappes and syn-kinematic gneissic granitoid sheets – not a core complex

Fowler

Khamees

Dowidar

2007

Journal of African Earth Sciences

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Section: El Sibai Granite and El Dabbah Granodioritementioning

confidence: 98%

“…It also contains mylonite zones. It has been identified as a highly differentiated late orogenic granite by El-Sayed et al (2002).…”

Section: Leucogranitesmentioning

confidence: 99%

El Sibai gneissic complex, Central Eastern Desert, Egypt: Folded nappes and syn-kinematic gneissic granitoid sheets – not a core complex

Fowler

Khamees

Dowidar

2007

Journal of African Earth Sciences

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“…The older granitoids are I-type, calc-alkaline intrusions, most likely originated by fractionation of mafic melts generated by partial melting of mantle wedge with little or no crustal contamination (e.g., Hussein et al, 1982) or by anatexis of granulitic lower crust in subduction zones (e.g., Furnes et al, 1996;Moghazi, 1999). The younger granites are A-type, alkaline to peralkaline series (e.g., El-Sayed, 1998;El-Sayed et al, 2002;Moghazi, 2002;Farahat et al, 2007;Ali et al, 2012a), formed in a post-collisional setting or anorogenic, rift-related environment (e.g., El-Sayed et al, 2002;Moghazi, 2002;Mohamed and El-Sayed, 2008). According to Greenberg (1981), the younger granites are thought to be derived from fractional crystallization of depleted upper mantle or lower crustal material (Moussa et al, 2008;Be'eri-Shlevin et al, 2009b).…”

Section: Geology Background and Petrographymentioning

confidence: 99%

Lu–Hf and O isotopic compositions on single zircons from the North Eastern Desert of Egypt, Arabian–Nubian Shield: Implications for crustal evolution

et al. 2016

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“…A late‐ to post‐orogenic affinity of the Deleihimmi granites has been further suggested by some authors (e.g. El Sayed et al ., 2002).…”

Section: Discussionmentioning

confidence: 99%

Neoproterozoic calc‐alkaline peraluminous granitoids of the Deleihimmi pluton, Central Eastern Desert, Egypt: implications for transition from late‐ to post‐collisional tectonomagmatic evolution in the northern Arabian–Nubian Shield

et al. 2011

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The widely distributed late-collisional calc-alkaline granitoids in the northern Arabian-Nubian Shield (ANS) have a geodynamic interest as they represent significant addition of material into the ANS juvenile crust in a short time interval . The Deleihimmi granitoids in the Egyptian Central Eastern Desert are, therefore, particularly interesting since they form a multiphase pluton composed largely of latecollisional biotite granitoids enclosing granodiorite microgranular enclaves and intruded by leuco-and muscovite granites. Geochemically, different granitoid phases share some features and distinctly vary in others. They display slightly peraluminous (ASI ¼ 1-1.16), non-alkaline (calc-alkaline and highly fractionated calc-alkaline), I-type affinities. Both biotite granitoids and leucogranites show similar rare earth element (REE) patterns [(La/Lu) N ¼ 3.04-2.92 and 1.9-1.14; Eu/Eu Ã ¼ 0.26-0.19 and 0.11-0.08, respectively) and related most likely by closed system crystal fractionation of a common parent. On the other hand, the late phase muscovite granites have distinctive geochemical features typical of rare-metal granites. They are remarkably depleted in Sr and Ba (4-35 and 13-18 ppm, respectively), and enriched in Rb (381-473 ppm) and many rare metals. Moreover, their REE patterns show a tetrad effect (TE 1,3 ¼ 1.13 and 1.29) and pronounced negative Eu anomalies (Eu/Eu Ã ¼ 0.07 and 0.08), implying extensive open system fractionation via fluid-rock interaction during the magmatic stage. Origin of the calc-alkaline granitoids by high degree of partial melting of mafic lower crust with subsequent crystal fractionation is advocated. The broad distribution of late-collisional calc-alkaline granitoids in the northern ANS is related most likely to large areal and intensive lithospheric delamination subsequent to slab break-off and crustal/mantle thickening. Such delamination caused both crustal uplift and partial melting of the remaining mantle lithosphere in response to asthenospheric uprise. The melts produced underplate the lower crust to promote its melting. The presence of microgranular enclaves, resulting from mingling of mantle-derived mafic magma with felsic crustalderived liquid, favours this process. The derivation of the late-phase rare-metal granites by open system fractionation via fluid interaction is almost related to the onset of extension above the rising asthenosphere that results in mantle degassing during the switch to post-collisional stage. Consequently, the switch from late-to post-collisional stage of crustal evolution in the northern ANS could be potentially significant not only geodynamically but also economically.

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Geochemistry and Petrogenesis of the Neoproterozoic Granitoids in the Central Eastern Desert, Egypt

Cited by 39 publications

References 65 publications

El Sibai gneissic complex, Central Eastern Desert, Egypt: Folded nappes and syn-kinematic gneissic granitoid sheets – not a core complex

El Sibai gneissic complex, Central Eastern Desert, Egypt: Folded nappes and syn-kinematic gneissic granitoid sheets – not a core complex

Lu–Hf and O isotopic compositions on single zircons from the North Eastern Desert of Egypt, Arabian–Nubian Shield: Implications for crustal evolution

Neoproterozoic calc‐alkaline peraluminous granitoids of the Deleihimmi pluton, Central Eastern Desert, Egypt: implications for transition from late‐ to post‐collisional tectonomagmatic evolution in the northern Arabian–Nubian Shield

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