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

Abstract

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 ...

Structural controls on non fabric‐selective dolomitization within rift‐related basin‐bounding normal fault systems: Insights from the Hammam Faraun Fault, Gulf of Suez, Egypt

“…Most limestone facies have been recrystallized and have a microcrystalline calcite texture, although skeletal (basinal) wackestones (B1) appear unaltered (Hirani, ). Basaltic dykes and sills provide the first stratigraphic evidence for rifting and have been dated as Oligo‐Miocene (24–22 Ma; Bosworth & Stockli, ).…”

Paleolithic artifact deposits at Wadi Dabsa, Saudi Arabia: A multiscalar geoarchaeological approach to building an interpretative framework

“…The most recently measured K‐Ar ages were obtained from a basalt flow south of the town of Al Birk, 20 km south of Wadi Dabsa, placing it at 1.37 ± 0.02 and 1.25 ± 0 0.02 Ma (G. N. Bailey et al, ). Given the wide variation in surface erosion of the lava flows, the Harrat was likely formed through an extended period of punctuated volcanism, related to intraplate volcanism similar to other Arabian harrat (Bosworth & Stockli, ). The timing of this volcanism places it within the known timeframe of the earliest dated hominin dispersals out of Africa, ~2.1 Ma (Zhu et al, ), meaning that it is possible that the landscape of the Harrat al Birk, and the resources it provided, underwent intermittent, significant transformation during the period in which hominin populations inhabited the region, changes which need to be understood before interpreting past hominin occupation of the region.…”

Palaeolithic artefact deposits at Wadi Dabsa, Saudi Arabia; a multi-scalar geoarchaeological approach to building an interpretative framework

“…The most recently-measured K-Ar ages were obtained from a basalt flow south of the town of Al Birk, 20 km south of Wadi Dabsa, placing it at 1.37 ± 0.02 and 1.25 ± 0 0.02 Ma . Given the wide variation in surface erosion of the lava flows, the Harrat was likely formed through an extended period of punctuated volcanism, related to intra-plate volcanism similar to other Arabian harrat (Bosworth & Stockli, 2016). The timing of this volcanism places it within the known timeframe of the earliest dated hominin dispersals out of Africa, ~1.8 Ma (Ferring et al 2011), meaning that it is possible that the landscape of the Harrat al Birk, and the resources it provided, underwent intermittent, significant transformation during the period in which hominin populations inhabited the region, changes which need to be understood before interpreting past hominin occupation of the region.…”