Mantle structure beneath Africa and Arabia from adaptively parameterized P-wave tomography: Implications for the origin of Cenozoic Afro-Arabian tectonism

Hansen, S. E.; Nyblade, A.; Benoit, M. H.

doi:10.1016/j.epsl.2011.12.023

Cited by 143 publications

(188 citation statements)

References 68 publications

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“…Large-scale mantle plumes emanating from large lowshear velocity provinces in the lower mantle, one below South Africa and one below the Pacific (Behn et al 2004;Torsvik et al 2006;Burke 2011;Bower et al 2013), are thought to be stable over tens or hundreds of millions of years (Glišović et al 2012;Bower et al 2013), suggesting a rather stable pattern of convection in the mantle. Strain pattern in the mantle below Africa, deduced from SKS seismic anisotropy, is furthermore compatible with northward mantle flow related to the African superplume (Bagley and Nyblade 2013;Hansen et al 2012). Similarly, the northward motion of Arabia, after its separation from Africa some 30 Ma ago, and the migration of hotspot-related volcanism toward the collision zone are also compatible with a northward asthenospheric flow dragging Africa and Arabia (Faccenna et al 2013b).…”

Section: Discussionsupporting

confidence: 57%

Neo-Tethys geodynamics and mantle convection: from extension to compression in Africa and a conceptual model for obduction

et al. 2016

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Since the Mesozoic, Africa has been under extension with shorter periods of compression associated with obduction of ophiolites on its northern margin. Less frequent than “normal” subduction, obduction is a first order process that remains enigmatic. The closure of the Neo-Tethys Ocean, by the Upper Cretaceous, is characterized by a major obduction event, from the Mediterranean region to the Himalayas, best represented around the Arabian Plate, from Cyprus to Oman. These ophiolites were all emplaced in a short time window in the Late Cretaceous, from ∼100 to 75 Ma, on the northern margin of Africa, in a context of compression over large parts of Africa and Europe, across the convergence zone. The scale of this process requires an explanation at the scale of several thousands of kilometres along strike, thus probably involving a large part of the convecting mantle. We suggest that alternating extension and compression in Africa could be explained by switching convection regimes. The extensional situation would correspond to steady-state whole-mantle convection, Africa being carried northward by a large-scale conveyor belt, while compression and obduction would occur when the African slab penetrates the upper–lower mantle transition zone and the African plate accelerates due to increasing plume activity, until full penetration of the Tethys slab in the lower mantle across the 660 km transition zone during a 25 Myr long period. The long-term geological archives on which such scenarios are founded can provide independent time constraints for testing numerical models of mantle convection and slab–plume interactions.

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Section: Discussionsupporting

confidence: 57%

Neo-Tethys geodynamics and mantle convection: from extension to compression in Africa and a conceptual model for obduction

et al. 2016

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“…anomaly beneath Afar seems to be rooted to a different direction from the African superplume [Debayle et al, 2001;Chang and van der Lee, 2011], casting doubt on the argument that a single large mantle plume has caused volcanic activity in East Africa [Nyblade, 2011;Hansen et al, 2012]. GAP_P4 does not discern the two low-velocity anomalies in the upper mantle, but it seems to show the root of the Afar plume reaching the uppermost lower mantle with a different direction from that of the African superplume, as shown in SGLOBE-rani.…”

Section: 1002/2014jb011824mentioning

confidence: 95%

Mapping the Moho with seismic surface waves: A review, resolution analysis, and recommended inversion strategies

2013

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“…In the case of Ethiopia, transition zone thickness, determined by receiver function analysis, shows evidence for thinning compared to the global mean; Cornwell et al (2011) cited this as evidence for high temperatures at transition zone depths, and thus connectivity between shallow low velocities imaged tomographically in Ethiopia (e.g., Bastow et al, 2008;Benoit et al, 2006;Debayle et al, 2001;Hansen et al, 2012;Pasyanos and Nyblade, 2007) and the superplume in the lower mantle beneath.…”

Section: Evidence From Broadband Seismologymentioning

confidence: 99%

“…The consensus emerging from recent studies in Ethiopia is that it is underlain by a broad low velocity anomaly, not a traditional narrow mantle plume (e.g., Bastow et al, 2008;Benoit et al, 2006;Cornwell et al, 2011;Hansen et al, 2012;Ritsema et al, 2010) (Fig. 5).…”

Section: Implications For the Thermochemical State Of The Ethiopian Mmentioning

confidence: 99%

The development of extension and magmatism in the Red Sea rift of Afar

et al. 2013

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Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of Arabia from Africa in the Afar depression is an ideal natural laboratory to address this problem since the region exposes subaerially the tectonically active transition from continental rifting to incipient seafloor spreading. We review recent constraints on along-axis variations in rift morphology, crustal and mantle structure, the distribution and style of ongoing faulting, subsurface magmatism and surface volcanism in the Red Sea rift of Afar to understand processes ultimately responsible for the formation of magmatic rifted continental margins. Our synthesis shows that there is a fundamental change in rift morphology from central Afar northward into the Danakil depression, spatially coincident with marked thinning of the crust, an increase in the volume of young basalt flows, and subsidence of the land towards and below sea-level. The variations can be attributed to a northward increase in proportion of extension by ductile plate stretching at the expense of magma intrusion. This is likely in response to a longer history of localised heating and weakening in a narrower rift. Thus, although magma intrusion accommodates strain for a protracted period during rift development, the final stages of breakup are dominated by a phase of plate stretching with a shift from intrusive to extrusive magmatism. This late-stage pulse of decompression melting due to plate thinning may be responsible for the formation of seaward dipping reflector sequences of basalts and sediments, which are ubiquitous at magmatic rifted margins worldwide.

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Mantle structure beneath Africa and Arabia from adaptively parameterized P-wave tomography: Implications for the origin of Cenozoic Afro-Arabian tectonism

Cited by 143 publications

References 68 publications

Neo-Tethys geodynamics and mantle convection: from extension to compression in Africa and a conceptual model for obduction

Neo-Tethys geodynamics and mantle convection: from extension to compression in Africa and a conceptual model for obduction

Mapping the Moho with seismic surface waves: A review, resolution analysis, and recommended inversion strategies

The development of extension and magmatism in the Red Sea rift of Afar

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