Petrology and geochemistry of the Tertiary Suez rift volcanism, Sinai, Egypt

Shallaly, N.A.; Beier, Christoph; Haase, Karsten M.; Hammed, Mohamed

doi:10.1016/j.jvolgeores.2013.10.005

Cited by 27 publications

(23 citation statements)

References 67 publications

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“…All of these volcanic units are generally sub-alkaline tholeiites (Baldridge et al 1991;Abdel Aal 1998;Endress et al 2011;Shallaly et al 2013) and no rhyolites of this age have been reported (Meneisy 1990). The basalts are temporally and spatially related to northwest-southeast faults that are present from the Libyan Plateau in the west to Sinai in the east.…”

Section: Egyptian Dikes and Flowsmentioning

confidence: 99%

Early magmatism in the greater Red Sea rift: timing and significance

Bosworth¹,

Stöckli

2016

Can. J. Earth Sci.

103

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Throughout the greater Red Sea rift system the initial late Cenozoic syn-rift strata and extensional faulting are closely associated with alkali basaltic volcanism. Older stratigraphic units are either pre-rift or deposited during pre-rupture mechanical weakening of the lithosphere. The East African superplume appeared in northeast Africa ϳ46 Ma but was not accompanied by any significant extensional faulting. Continental rifting began in the eastern and central Gulf of Aden at ϳ31-30 Ma coeval with the onset of continental flood volcanism in northern Ethiopia, Eritrea, and western Yemen. Volcanism appeared soon after at Derudeb in southern Sudan and at Harrats Hadan and As Sirat in Saudi Arabia. From ϳ26.5 to 25 Ma a new phase of volcanism began with the intrusion of a dike field reaching southeast of Afar into the Ogaden. At 24-23 Ma dikes were emplaced nearly simultaneously north of Afar and reached over 2000 km into northern Egypt. The dike event linked Afar to the smaller Cairo mini-plume and corresponds to initiation of lithospheric extension and rupture in the central and northern Red Sea and Gulf of Suez. By ϳ21 Ma the dike intrusions along the entire length of the Red Sea were completed. Each episodic enlargement of the greater Red Sea rift system was triggered and facilitated by breakthrough of mantle-derived plumes. However, the absence of any volumetrically significant rift-related volcanism during the main phase of Miocene central and northern Red Sea -Gulf of Suez rifting supports the interpretation that plate-boundary forces likely drove overall separation of Arabia from Africa.Résumé : Dans l'ensemble du grand système du rift de la mer Rouge, les strates initiales syn-rifting et l'extension par failles d'âge cénozoïque tardif sont étroitement associées à un volcanisme basaltique alcalin. Les unités stratigraphiques plus anciennes précèdent la formation du rift ou ont été déposées durant l'affaiblissement mécanique de la lithosphère qui a précédé la rupture. Le superpanache est-africain est apparu dans le nord-est de l'Afrique à ϳ46 Ma, mais n'était pas accompagné d'une importante déformation par failles. Le rifting continental a commencé dans l'est et le centre du golfe d'Aden à ϳ31-30 Ma, en même temps que le début du volcanisme continental de plateau dans le nord de l'Éthiopie, en Érythrée et dans l'ouest du Yémen. Le volcanisme est apparu peu après à Derudeb, dans le sud du Soudan, et aux Harrats Hadan et As Sirat, en Arabie saoudite. À partir de ϳ26,5-25 Ma, une nouvelle phase de volcanisme a débuté avec l'intrusion d'un essaim de dykes allant du sud-est d'Afar jusque dans l'Ogaden. À 24-23 Ma, des dykes ont été mis en place presque simultanément au nord d'Afar et s'étalant sur plus de 2000 km jusque dans le nord de l'Égypte. L'intrusion de dykes a relié Afar au mini-panache plus petit du Caire et correspond au début de la distension et de la rupture lithosphériques dans le centre et le nord de la mer Rouge et le golfe de Suez. À ϳ21 Ma, l'intrusion de dykes sur toute la longueur de ...

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Section: Egyptian Dikes and Flowsmentioning

confidence: 99%

Early magmatism in the greater Red Sea rift: timing and significance

Bosworth¹,

Stöckli

2016

Can. J. Earth Sci.

103

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“…The Nb/Ta ratios (15.5–17) indicate mantle‐derived melts and are analogous to those of the Tertiary basalts from south‐western Sinai and south Quseir (Farahat et al, ; Green, ; Shallaly et al, ). Moreover, these ratios are identical to OIB‐like asthenospheric melts (Pfänder et al, 2012).…”

Section: Discussionmentioning

confidence: 78%

“…However, the Sr–Nd isotopic data suggest that the Afar plume‐like component was not involved in the origin of the Egyptian basaltic volcanism (Endress, ; Endress et al, ). Moreover, the Egyptian basalts were generated by lower melting degrees (<10%; Figure b;e.g., Farahat et al, ; Shallaly et al, ) which indicate low volumes of the basaltic lavas erupted and low eruption rates. This inference suggests that the mantle potential temperature was low, consistent with ambient mantle temperatures (i.e., passive mantle upwelling).…”

Section: Discussionmentioning

confidence: 99%

“…Continental rift and associated processes (i.e., rift origination and related volcanic activity, structures, and crustal uplifting) are attributed to passive and/or active (i.e., plume) mantle upwelling and are a matter of current debate (e.g., Ali et al, 2013;Ali & Ntaflos, 2011;Bosworth et al, 2015;Buck, 2006;Chang & Van der Lee, 2011;Courtillot et al, 1999;Endress, 2010;Farahat et al, 2017;Farahat, Ghani, Aboazom, & Asran, 2006;Shallaly et al, 2013).…”

Section: Regional Geodynamic Evolutionmentioning

confidence: 99%

“…Extension most likely due to the NE-SW tensional stresses which reactivated the old fractures and triggered mafic magma generation through passive upwelling of the asthenospheric mantle. Continental intraplate magmatic provinces are characterized by mafic magmas generation due to lithospheric extension and/or mantle plume activity (Ali & Ntaflos, 2011;Ali, Ntaflos, & Upton, 2013;Baker, Snee, & Menzies, 1996;Bosworth, Stockli, & Helgeson, 2015;Courtillot, Jaupart, Manighetti, Tapponnier, & Besse, 1999;Endress, 2010;Farahat, Ali, & Hauzenberger, 2017;Hofmann et al, 1997;Pik, Deniel, Coulon, Yirgu, & Marty, 1999;Shallaly, Beier, Haase, & Hammed, 2013). Red Sea district represents one of the youngest continental intraplate magmatic provinces (Figure 1a).…”

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confidence: 99%

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Origin and geotectonic evolution of Mir Tertiary basaltic andesite dykes, Western Desert, Egypt: Constraints from mineral and bulk‐rock chemistry

Farahat

Ali

2018

Geological Journal

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Compared with widespread Egyptian Tertiary basaltic rocks, Mir Tertiary basaltic dykes from the Western Desert of Egypt show distinct mineralogical and geochemical characteristics that provide insights into the nature of their mantle source and geotectonic evolution as well as melting and crystallization conditions. Their mineralogical features (i.e., presence of orthopyroxene and lack of olivine) distinguish them from the other Egyptian Tertiary basalts. They have basaltic andesite compositions (SiO2 = 53.55–55 wt.%, Na2O + K2O = 4.64–4.8 wt.%, MgO = 2.66–3.02 wt.%) with tholeiitic character. Temperature of crystallization ranges from 1,112°C to 1,140°C for plagioclase; from 1,085°C to 1,123°C for clinopyroxene; and from 1,034°C to 1,090°C for orthopyroxene. These results are in harmony with petrographic observations which suggest early crystallization of plagioclase, followed by simultaneous crystallization of plagioclase and clinopyroxene, and soon thereafter by orthopyroxene crystallization. Titanomagnetite–ilmenite intergrowths indicate oxygen fugacity (ƒO2) of −12.09 and −9.4 log units, suggesting crystallization at relatively oxidized conditions. Their temperature ranges from 959°C to 1,125°C, suggesting that the titanomagnetite joins the crystallized phases at early stages and continued until later stages. Mir basaltic andesite (MBA) has low Ni (15–27.9 ppm), Cr (19.8–48.5 ppm), and Sc (20–25 ppm) concentrations together with high FeOt/MgO ratios (3.18–3.58) relative to primitive basalts, arguing for their evolved nature. They have sub‐chondritic Nb/Ta ratios (15.5–17) similar to ocean–island basalts and higher than those of continental crust, ruling out a significant effect of crustal contamination. The high La/Nb (>1.4) with the negative Nb, Ta, and Ti anomalies on the primitive mantle‐normalized patterns most likely indicates that their primary magma was derived from partial melting of a mantle source previously metasomatized by influx of subduction‐related slab fluids/melts. Moreover, the super‐chondritic Zr/Hf ratios (39.55–55.21) and the negative K and Ti anomalies point to carbonate metasomatism of their mantle source. This inference is further supported by their high (K2O + Na2O)/TiO2 ratios (>1) which are comparable with experimentally produced carbonated peridotite melts. The high Zr/Y (average 9.75) and La/Yb ratios (8.6–10) of the MBA suggest that they were generated via low degrees of partial melting. Indeed, modelling calculations indicate generation by lower melting degrees (<10%) of a garnet‐bearing lherzolite mantle source. The melting region was at the garnet stability field suggesting a deeper origin (exceeds ~85 km) for MBA. Field and geochemical characteristics of the Egyptian Tertiary volcanism proved that it is spatially and temporally related to extension that has occurred during Red Sea rifting. Extension most likely due to the NE–SW tensional stresses which reactivated the old fractures and triggered mafic magma generation through passive upwelling of the asthenospheric mantle.

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Timing of Extensional Faulting Along the Magma-Poor Central and Northern Red Sea Rift Margin—Transition from Regional Extension to Necking Along a Hyperextended Rifted Margin

Stöckli

Bosworth²

2018

Geological Setting, Palaeoenvironment and Archaeology of the Red Sea

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Petrology and geochemistry of the Tertiary Suez rift volcanism, Sinai, Egypt

Cited by 27 publications

References 67 publications

Early magmatism in the greater Red Sea rift: timing and significance

Early magmatism in the greater Red Sea rift: timing and significance

Origin and geotectonic evolution of Mir Tertiary basaltic andesite dykes, Western Desert, Egypt: Constraints from mineral and bulk‐rock chemistry

Timing of Extensional Faulting Along the Magma-Poor Central and Northern Red Sea Rift Margin—Transition from Regional Extension to Necking Along a Hyperextended Rifted Margin

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