Timing of the Ethiopian flood basalt event and implications for plume birth and global change

Hofmann, C.; Courtillot, Vincent; Féraud, Gilbert; Rochette, P.; Yirgu, Gezahegn; Ketefo, Endale; Pik, R.

doi:10.1038/39853

Cited by 627 publications

(390 citation statements)

References 28 publications

(21 reference statements)

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“…1). The stratigraphically lowest sampled basalt gave a whole-rock plateau age of 30.8 ± 0.4 Ma (Hofmann et al (1997) reported confidence levels at 1). A slightly higher basalt in another section provided a plagioclase isochron age of 31.3 ± 0.7 Ma.…”

Section: Afar and The Ethiopian Plateaumentioning

confidence: 99%

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

Bosworth¹,

Stöckli

2016

Can. J. Earth Sci.

101

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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: Afar and The Ethiopian Plateaumentioning

confidence: 99%

“…More recent 40 Ar/ 39 Ar data have significantly revised this picture. Hofmann et al (1997) studied three sections in the northern Ethiopian plateau west of Afar and the basalt outliers to the north at Adigrat (Fig. 1).…”

Section: Afar and The Ethiopian Plateaumentioning

confidence: 99%

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

Bosworth¹,

Stöckli

2016

Can. J. Earth Sci.

101

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“…This area is stretched by the separation of the Africa and Arabia plate, whose boundaries correspond to the Aden and Red Sea Ridge (Figure 2a). The Africa-Arabia separation was initiated 30 Myr ago [e.g., Hofmann et al, 1997;Courtillot et al, 1999] by the activity of a mantle plume leading to intraplate volcanism [e.g., Schilling, 1973;White and McKenzie, 1989;Marty et al, 1993;Deniel et al, 1994;Courtillot et al, 1999]. The Afar area is characterized by active rifting taking place along several disconnected rift segments propagating on land ( Figure 2a) [e.g., Varet and Gasse, 1978;Courtillot, 1980;Manighetti et al, 1998].…”

Section: Geological and Geophysical Constraintsmentioning

confidence: 99%

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Pinzuti

Humler

Manighetti

2013

Geochem Geophys Geosyst

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[1] The temporal evolution of the mantle melting processes in the Asal Rift is evaluated from the chemical composition of 56 new lava flows sampled along 10 km of the rift axis and 9 km off-axis (i.e., erupted within the last 620 kyr). Petrological and primary geochemical results show that most of the samples of the inner floor of the Asal Rift are affected by plagioclase accumulation. Trace element ratios and major element compositions corrected for mineral accumulation and crystallization show a symmetric pattern relative to the rift axis and preserved a clear signal of mantle melting depth variations. While FeO, Fe 8.0 , Zr/Y, and (Dy/Yb) N decrease from the rift shoulders to the rift axis, SiO 2 , Na/Ti, Lu/Hf increase and Na 2 O and Na 8.0 are constant across the rift. These variations are qualitatively consistent with shallow melting beneath the rift axis and deeper melting for off-axis lava flows. Na 8.0 and Fe 8.0 contents show that beneath the rift axis, melting paths are shallow, from 81 6 4 to 43 6 5 km. These melting paths are consistent with adiabatic melting in normal-temperature fertile asthenosphere, beneath an extensively thinned mantle lithosphere. On the contrary, melting on the rift shoulders (from 107 6 7 to 67 6 8 km) occurred beneath thicker lithosphere, requiring a mantle solidus temperature 100 6 40 C hotter. In this geodynamic environment, the calculated rate of lithospheric thinning appears to be 4.0 6 2.0 cm yr À1 , a value close to the mean spreading rate (2.9 6 0.2 cm yr À1 ) over the last 620 kyr.

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“…Hofmann et al 1997;Wolfenden et al 2005). The Arabia -Africa separation created the Danakil microplate, a sliver of stretched continental crust that forms a horst between the highly extended Afar Depression, and the southern Red Sea rift zone (Fig.…”

Section: Tectonic Settingmentioning

confidence: 99%

“…1), which is being pulled NE by the subducting Tethys oceanic lithosphere (e.g. Hofmann et al 1997;Bellahsen et al 2003;Wolfenden et al 2005). From decades of geodetic observations, the current plate motion velocities relative to Nubia are estimated to be c. 15 mm a 21 of NE-directed motion of the Danakil Block (Vigny et al 2007;McClusky et al 2010) and c. 2-6 mm a 21 of ESE motion of the Somalian Plate (e.g.…”

Section: Tectonic Settingmentioning

confidence: 99%

Seismicity of the central Afar rift and implications for Tendaho dam hazards

Ayele

Ebinger

Alstyne

et al. 2015

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Temporary broadband seismic networks deployed from 2007 to 2011 around the Afar triple junction of the East African Rift System provide insights into seismicity patterns of the actively deforming crust around the 1.86 km 3 impounded lake system behind the Tendaho dam. The observed seismicity correlates well with the active magmatic centres around central Afar. The area around the dam site is characterized by a network of intersecting NNE-and NW-trending faults. Seismicity clusters observed in the specified time interval indicate that both fault sets are active and are potential sources of seismogenic hazards. The dam neighbourhood is naturally active and it is a challenge to associate the observed seismic activity to either a change in magmato-tectonic conditions or attribute it to the influence of reservoir load. It is evident that the dam region experiences high levels of seismic and volcano-tectonic unrest, regardless of the origin of the activity. The spatial overlap of narrow zones of crustal seismicity and upper mantle low velocity zones observed in S-wave tomography models suggests that melt production zones guide the distribution of strain during continental rupture. Given its volcanically and seismically active setting, the Tendaho dam site and the surrounding region require continuous monitoring for the safety of downstream populations and development infrastructures in the Afar National Regional State of Ethiopia.

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Timing of the Ethiopian flood basalt event and implications for plume birth and global change

Cited by 627 publications

References 28 publications

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

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

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Seismicity of the central Afar rift and implications for Tendaho dam hazards

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