Lithostratigraphy and tectonic evolution of the Meatiq infrastructure, central eastern desert, Egypt

Habib, Mohamed E.; Ahmed, Amany A.; El-Nady, Osman M.

doi:10.1016/0301-9268(82)90098-5

Cited by 3 publications

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“…It is formed mainly of mylonitic rocks, previously described as infrastructure, constituting part of Pre -Neoproterozoic continental crust, overthrust by juvenile Pan-African supracrustal rocks (e.g. Habib et al, 1982;El Gaby et al, 1983;Habib et al, 1985;El Gaby et al, 1988;Khudeir et al, 2008). However, other authors considered these infrastructure rocks to represent juvenile Neoproterozoic crust (e.g.…”

Section: Introductionmentioning

confidence: 99%

Geological Studies on the Abu Fannani Mylonitic Amphibolites and Related Amphibolite Xenoliths in the Juvenile Neoproterozoic Meatiq Dome Area, Central Eastern Desert, Egypt.

2019

Assiut University Journal of Multidisciplinary Scientific Resea

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The Neoproterozoic crustal rocks exposed in the Meatiq dome area, Central Eastern Desert of Egypt, comprise medium -to high -grade mylonites. They form strongly foliated and folded mappable units, including (in the core): Um Baanib granite-gneiss, followed structurally upward by Fiadiya augen schists, Gabal Meatiq phyllonitic mylonites, Abu Zohleiqa augen gneisses, Um Esh El-hamra quartzofeldspathic mylonites, and Abu Fannani mylonitic amphibolites. These appear to have been largely derived from granitic, pelitic to semipelitic, and basaltic to basaltic andesite rocks. The present work is focused only on the Abu Fannani mylonitic amphibolites which occur mainly in the shear zone constituting the frame of the Meatiq Dome. The amphibolite xenoliths hosted by the Um Baanib granite-gneiss are supposed to be originally belonging to the Abu Fannani unit. Field and petrographic characteristics of both amphibolitic types indicate that they were undergone a complex evolution of repeated deformations and metamorphisms. These were genetically connected with three major events, including subduction, obduction and updoming processes. Due to subduction, the original basaltic to basaltic andesites, together with the pelitic to semipelitic sediments formed a strongly folded and highly metamorphosed (M 1 ) orogenic belt. The lower part of this belt was migmatized and intruded by a synkinematic granite (i.e., Um Baanib granite-gneiss). During obduction, thick nappes overrode the highly metamorphosed belt leading to its transformation into high-to mediumgrade mylonites having the amphibolite facies grade metamorphism (M 2 ). Thereafter, updoming processes originally linked with the Najd Fault System took place where brittle-ductile shear zones accompanied with greenschist facies metamorphism (M 3 ) were achieved. Regarding geochemistry of the amphibolites, major elements refer to their derivation from tholeiitic basalt to basaltic andesites. In Harker variation diagrams, immobile and incompatible elements (Zr,Ti,Y, and P) show good linear correlation relative to the mobile elements. Tectonic discrimination diagrams suggest the presence of two tectonic settings for both amphibolites, i.e., within-plate and MORB environments.

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Section: Introductionmentioning

confidence: 99%

Geological Studies on the Abu Fannani Mylonitic Amphibolites and Related Amphibolite Xenoliths in the Juvenile Neoproterozoic Meatiq Dome Area, Central Eastern Desert, Egypt.

2019

Assiut University Journal of Multidisciplinary Scientific Resea

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Structural geology, single zircon ages and fluid inclusion studies of the Meatiq metamorphic core complex: Implications for Neoproterozoic tectonics in the Eastern Desert of Egypt

Loizenbauer

2001

Precambrian Research

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Tectonic evolution of the Meatiq infrastructure, Central Eastern Desert, Egypt

Habib¹,

Ahmed²,

Nady³

1985

Tectonics

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The Pan‐African basement exposed in the Meatiq area, Central Eastern Desert, Egypt, was found to possess tectonic styles belonging to infrastructure, transition and super‐structure levels. Tectonic style of the infrastructure was developed during an old orogeny in the Lower Pan‐African, and overprinted by those of the transition and superstructure levels of a younger orogeny in the Middle and Upper Pan‐African, respectively. In the Lower Pan‐African, old sequences of sediments and volcanics, together with ophiolitic rocks, were intensely deformed and regionally highly metamorphosed into gneisses and amphibolites. In the infrastructure level such rocks were migmatized, plastically deformed and intruded by synkinematic granitoid (diorite to alkali granite) lenses, sheets and plutons which were probably crystallized as amphibolite‐facies gneisses. Later on, these infrastructural rocks were cut by mafic to intermediate dykes and sills, isostically uplifted and cratonized. Parts were exposed to erosion. In the Middle Pan‐African the cratonized rocks sank into a transition tectonic level where they underwent large‐scale thrusting, varying degrees of cataclasis and mylonitization, and low‐ to medium‐grade regional metamorphism. An episode of plutonism guided by thrusts followed, mainly in the form of synkinematic intrusion of tonalite, granodiorite and quartz monzodiorite. In the Upper Pan‐African, isostatic uplift occurred and the mylonitic rocks attained the superstructure level. There they were subjected to two main phases of folding resulting in the major Meatiq domal structure. Subsequently, the folded rocks were intruded by a postkinematic quartz monzonite pluton.

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Lithostratigraphy and tectonic evolution of the Meatiq infrastructure, central eastern desert, Egypt

Cited by 3 publications

References 0 publications

Geological Studies on the Abu Fannani Mylonitic Amphibolites and Related Amphibolite Xenoliths in the Juvenile Neoproterozoic Meatiq Dome Area, Central Eastern Desert, Egypt.

Geological Studies on the Abu Fannani Mylonitic Amphibolites and Related Amphibolite Xenoliths in the Juvenile Neoproterozoic Meatiq Dome Area, Central Eastern Desert, Egypt.

Structural geology, single zircon ages and fluid inclusion studies of the Meatiq metamorphic core complex: Implications for Neoproterozoic tectonics in the Eastern Desert of Egypt

Tectonic evolution of the Meatiq infrastructure, Central Eastern Desert, Egypt

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