Geological evolution of the Afro-Arabian dome

Almond, D.C.

doi:10.1016/0040-1951(86)90180-0

Cited by 126 publications

(40 citation statements)

References 37 publications

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“…It has been suggested that only Archean lithosphere has a chemically distinct tectosphere, because the thermal state of the Earth may have changed at the Archean-Proterozoic boundary [Richter, 1988]. Second, Saudi Arabia has not been tectonically stable since its formation [Almond, 1986]. Continental rifting commencing at 30 to 20 Ma separated the formerly conjoined Arabian and Nubian Shields and created the Red Sea spreading center, and several volcanic fields in western Saudi Arabia erupted from 30 Ma to Recent [Camp and Roobol, 1992].…”

Section: Introductionmentioning

confidence: 99%

Shear‐wave splitting across western Saudi Arabia: The pattern of upper mantle anisotropy at a Proterozoic Shield

Wolfe

Vernon

Alamri

1999

Geophysical Research Letters

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Abstract. We constrain upper mantle anisotropy across the Arabian Shield from shear-wave splitting analyses of $K$ phases at eight temporary broadband stations that operated in Saudi Arabia. The direction of fast polarization is consistently aligned north-south and the delay time between fast and slow shear waves is generally 1.0 to 1.5 s, indicating that the mantle anisotropy is relatively homogeneous and coherent. We cannot distinguish between two possible models for the origin of this signal. The observed splitting may reflect fossil upper mantle anisotropy associated with the dominantly east-west accretion of oceanic terranes and formation of the Proterozoic Arabian lithosphere. Our results may also be compatible with present-day asthenospheric anisotropy caused by the northward absolute plate motion of the Arabian plate or northward asthenospheric flow from an Ethiopian mantle plume.

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Section: Introductionmentioning

confidence: 99%

Shear‐wave splitting across western Saudi Arabia: The pattern of upper mantle anisotropy at a Proterozoic Shield

Wolfe

Vernon

Alamri

1999

Geophysical Research Letters

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“…1), and this extensive province of volcanism has intrigued and puzzled geoscientists since they were first recognized. Why long-lived and voluminous magmatic activity has occurred east of the Red Sea rift has evoked numerous interpretations but not consensus (e.g., Gass 1970;Almond 1986aAlmond , 1986bRoobol 1989, 1992).…”

Section: Saudi Arabia Older Harratsmentioning

confidence: 99%

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

Bosworth¹,

Stöckli

2016

Can. J. Earth Sci.

105

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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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“…A continuous mantle of chaotic boulder-dominated reddish debris (Hintalo Giyorgis Unit), emplaced by slope wash and mass movements, is found at the base of the upper escarpment down to 2450 m. Remnants of the same materials are also present on top of isolated small hills down to 2150 m. Their distribution along the slope suggests the existence of an ancient depositional glacis overlying a pediment-like surface, formed by retreat of the Amba Aradam Formation escarpment and later dissected by the present drainage network. Due to their morpho-stratigraphic position, these materials constitute the oldest geomorphic-sedimentary unit of the area, deposited after erosion associated with the late Tertiary-Quaternary uplift (Almond, 1986) and can be generically referred to the Early-Middle Pleistocene. More recent slope-waste deposits and debris cones, made of poorly sorted angular and sub-angular, locally stratified debris fragments, are largely present in the western sector of the slopes and at the foot of the main escarpment.…”

Section: Landforms Due To Gravitymentioning

confidence: 99%

The Geomorphological Map of Mt. Amba Aradam Southern Slope (Tigray, Ethiopia)

et al. 2009

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The geomorphological map described below covers an area of about 100 km 2 , located on the southeastern slope of Mt. Amba Aradam (northern Ethiopia). It has been produced within the Ethio-Italian Cooperation Programme, in order to understand the recent evolution and present-day trends of the area as a basic tool for land reclamation/rehabilitation projects. The survey was carried out in three successive work campaigns

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Geological evolution of the Afro-Arabian dome

Cited by 126 publications

References 37 publications

Shear‐wave splitting across western Saudi Arabia: The pattern of upper mantle anisotropy at a Proterozoic Shield

Shear‐wave splitting across western Saudi Arabia: The pattern of upper mantle anisotropy at a Proterozoic Shield

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

The Geomorphological Map of Mt. Amba Aradam Southern Slope (Tigray, Ethiopia)

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