Dating of late Proterozoic ophiolites in Egypt and the Sudan using the single grain zircon evaporation technique

Kröner, Alfred; Todt, W.; Hussein, I.M.; Mansour, M.; Rashwan, A.A.

doi:10.1016/0301-9268(92)90049-t

Cited by 239 publications

(72 citation statements)

References 38 publications

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“…This age is comparable to that determined for other ophiolite fragments in southern Egypt and Sudan that range in age between ca. 800 and 720 Ma (Kröner et al 1992). Being part of a tectonic mèlange (Ries et al 1983) no further conclusions can be drawn regarding the age of the surrounding low-grade metasediments and metavolcanics.…”

Section: Geological Interpretationsmentioning

confidence: 94%

“…Published ages on the ophiolites within the eugeoclinal thrust sheet in Egypt and Sudan range between 880 and 740 Ma (Ries et al 1983;Kröner 1985;Kröner et al 1992Kröner et al , 1994Stern 1994;Loizenbauer et al 2001), with two age maxima from about 850 to 780 Ma and from 750 to 700 Ma (Stern 1994). The geochemistry of the Fawakhir Ophiolite, located a few kilometers SW of the Meatiq Gneiss Dome, has been described in several publications (e.g.…”

Section: Plutonic Rocks and Previous Geochronologymentioning

confidence: 97%

“…Ophiolites within the East African Orogen in the Eastern Desert, interpreted as oceanic crust formed by rifting of Rodinia, have yielded ages between 900 and 740 Ma (Ries et al 1983;Kröner 1985;Kröner et al 1992Kröner et al , 1994Loizenbauer et al 2001). The ophiolite fragment dated to ca.…”

Section: Regional Geologymentioning

confidence: 98%

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U–Pb TIMS age constraints on the evolution of the Neoproterozoic Meatiq Gneiss Dome, Eastern Desert, Egypt

Andresen

El-Rus

Myhre

et al. 2007

Int J Earth Sci (Geol Rundsch)

168

121

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Ages are used to constrain the temporal evolution of the Meatiq Gneiss Dome, Eastern Desert, Egypt, by dating (ID-TIMS) pre-, syn-, and post-tectonic igneous rocks in and around the dome. The Um Ba'anib Orthogneiss, comprising the deepest exposed structural levels of the dome, has a crystallization age of 630.8 ± 2 Ma. The overlying mylonites are interpreted to be a thrust sheet/ complex (Abu Fannani Thrust Sheet) of highly mylonitized metasediments (?), migmatitic amphibolites, and orthogneisses with large and small tectonic lenses of lessdeformed intrusives. Two syn-tectonic diorite lenses in this complex have crystallization ages of 609.0 ± 1.0 and 605.8 ± 0.9 Ma, respectively. The syn-tectonic Abu Ziran diorite, cutting across the tectonic contact between mylonite gneisses of the Abu Fannani Thrust Sheet and a structurally overlying thrust sheet of eugeoclinal rocks (''Pan-African nappe''), has a magmatic emplacement age of 606.4 ± 1.0 Ma. Zircons from a gabbro (Fawakhir ophiolite) within the eugeoclinal thrust sheet yielded a crystallization age of 736.5 ± 1.2 Ma. The post-tectonic Fawakhir monzodiorite intrudes the ophiolitic rocks and has an emplacement age of 597.8 ± 2.9 Ma. Two other post-tectonic granites, the Arieki granite that intrudes the foliated Um Ba'anib Orthogneiss, and the Um Had granite that cuts the deformed Hammamat sediments, have emplacement ages of 590 ± 3.1 and 596.3 ± 1.7 Ma, respectively. We consider formation of the Meatiq Gneiss Dome to be a young structural feature (\631 Ma), and our preferred tectonic interpretation is that it formed as a result of NE-SW shortening contemporaneous with folding of the nearby Hammamat sediments around 605-600 Ma, during oblique collision of East and West Gondwana.

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Section: Geological Interpretationsmentioning

confidence: 94%

Section: Plutonic Rocks and Previous Geochronologymentioning

confidence: 97%

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U–Pb TIMS age constraints on the evolution of the Neoproterozoic Meatiq Gneiss Dome, Eastern Desert, Egypt

Andresen

El-Rus

Myhre

et al. 2007

Int J Earth Sci (Geol Rundsch)

168

121

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“…In this instance our data record a period of granitoid activity for this suite extending from ~750 to ~680 Ma as also found by Stern and Hedge (1985) for deformed granitoid rocks elsewhere in the southern ED. This plutonism reflects a period of magmatic arc formation which is virtually coeval with the formation of oceanic crust nearby, as represented by the Wadi Ghadir ophiolite dated at 745 + 25 Ma (Kr6ner et al, 1992).…”

Section: Zircon Agesmentioning

confidence: 99%

Age and tectonic setting of granitoid gneisses in the Eastern Desert of Egypt and south-west Sinai

Kr�ner¹,

Kr�ger

Rashwan

1994

Geol Rundsch

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Strongly deformed and locally migmatized gneisses occur at several places in the southern Eastern Desert of Egypt and in Sinai and have variously been interpreted as a basement to Pan-african (~900 to 600 Ma) supracrustal and intrusive assemblages. A suite of grabbroic to granitic gneisses was investigated in the Hafafit area, which constitutes an I-type calc-alkaline intrusive assemblage whose chemistry suggests emplacement along an active continental margin and whose granitoid members can be correlated with the so-called 'Older Granites' of Egypt. 2°7pb/2°6pb single zircon evaporation from three samples of the Hafafit gneisses yielded protolith emplacement ages between 677 + 9 and 700 _+ 12 Ma and document granitoid activity over a period of about 23 Ma. A migmatitic granitic gneiss from Wadi Bitan, south-west of Ras Banas, has a zircon age of 704 + 8 Ma, and its protolith was apparently generated during the same intrusive event as the granitoids at Hafafit. Single zircons from a dioritic gneiss from Wadi Feiran in south-west Sinai suggest emplacement of the protolith at 796 + 6 Ma and this is comparable with ages for granitoids in north-east Sinai and southern Israel. None of the above gneisses is derived from remelting of older continental crust, but they are interpreted as reflecting subduction-related calc-alkaline magmatism during early Pan-african magmatic arc formation.

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“…Kröner et al 1992;Shackleton 1994;Zimmer et al 1995;Loizenbauer et al 2001;Ali et al 2010). They have isotopic ages range from 890 to 690 Ma, documenting a 200 Ma year period of oceanic magmatism.…”

mentioning

confidence: 99%

Petrological studies of neoproterozoic serpentinized ultramafics of the nubian shield: spinel compositions as evidence of the tectonic evolution of egyptian ophiolites

Azer¹

2014

Acta Geologica Polonica

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The mafic-ultramafic rocks of the Gabal El-Degheimi area, Central Eastern Desert of Egypt, are parts of an ophiolitic section. The ophiolitic rocks are dismembered and tectonically enclosed within, or thrust over, island arc assemblages. Serpentinites, altered slices of the upper mantle, represent a distinctive lithology of the dismembered ophiolites. Some portions of the serpentinized rocks contain fresh relicts of primary minerals such as chromian spinel and olivine. The abundance of bastite and mesh textures suggests harzburgite and dunite protoliths, respectively, for these serpentinites. Some fresh cores of chromian spinel are rimmed by ferritchromite and Cr-magnetite. The development of alteration rims around chromian spinel cores indicates their formation during prograde alteration and under oxidizing conditions during lower amphibolite facies metamorphism. Fresh chromian spinels are characterized by high contents of Cr2O3 (48.92-56.74 wt. %), Al2O3 (10.29-20.08wt. %), FeO (16.24-28.46 wt. %) and MgO (4.89-14.02 wt. %), and very low TiO2 contents (<0.16 wt. %). The analyzed fresh chromian spinels have high Cr# (0.62-0.79) characteristic of spinels in mantle peridotite that has undergone some degree of partial melting. The data presented here suggest that the mantle peridotites of the Gabal El-Degheimi area are similar to forearc peridotites of suprasubduction zone environments.

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Dating of late Proterozoic ophiolites in Egypt and the Sudan using the single grain zircon evaporation technique

Cited by 239 publications

References 38 publications

U–Pb TIMS age constraints on the evolution of the Neoproterozoic Meatiq Gneiss Dome, Eastern Desert, Egypt

U–Pb TIMS age constraints on the evolution of the Neoproterozoic Meatiq Gneiss Dome, Eastern Desert, Egypt

Age and tectonic setting of granitoid gneisses in the Eastern Desert of Egypt and south-west Sinai

Petrological studies of neoproterozoic serpentinized ultramafics of the nubian shield: spinel compositions as evidence of the tectonic evolution of egyptian ophiolites

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