Upper mantle structure of the southern Arabian margin: Insights from teleseismic tomography

Korostelev, Félicie; Leroy, Sylvie; Keir, Derek; Ahmed, Abdulhakim; Boschi, Lapo; Rolandone, F.; Stuart, G. W.; Obrebski, Mathias; Khanbari, Khaled; El‐Hussain, Issa

doi:10.1130/ges01159.1

Cited by 11 publications

(13 citation statements)

References 83 publications

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“…Geochemistry, Geophysics, Geosystems 2013; Khoza et al, 2013;Korostelev et al, 2015Korostelev et al, , 2016Leseane et al, 2015;Mulibo & Nyblade, 2013b;Nita et al, 2016;Nyblade, 2011;Nyblade & Brazier, 2002;Nyblade et al, 2000;Reed, Gao, et al, 2016;Ritsema et al, 2011Ritsema et al, , 1998Slack et al, 1994;Sun et al, 2017;Yu et al, 2015).…”

Section: 1029/2018gc007804mentioning

confidence: 99%

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Emry

Shen

Nyblade

et al. 2019

Geochem Geophys Geosyst

152

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Our understanding of the tectonic development of the African continent and the interplay between its geological provinces is hindered by unevenly distributed seismic instrumentation. In order to better understand the continent, we used long‐period ambient noise full‐waveform tomography on data collected from 186 broadband seismic stations throughout Africa and surrounding regions to better image the upper mantle structure. We extracted empirical Green's functions from ambient seismic noise using a frequency‐time normalization method and retrieved coherent signal at periods of 7–340 s. We simulated wave propagation through a heterogeneous Earth using a spherical finite‐difference approach to obtain synthetic waveforms, measured the misfit as phase delay between the data and synthetics, calculated numerical sensitivity kernels using the scattering integral approach, and iteratively inverted for structure. The resulting images of isotropic, shear wave speed for the continent reveal segmented, low‐velocity upper mantle beneath the highly magmatic northern and eastern sections of the East African Rift System (EARS). In the southern and western sections, high‐velocity upper mantle dominates, and distinct, low‐velocity anomalies are restricted to regions of current volcanism. At deeper depths, the southern and western EARS transition to low velocities. In addition to the EARS, several low‐velocity anomalies are scattered through the shallow upper mantle beneath Angola and North Africa, and some of these low‐velocity anomalies may be connected to a deeper feature. Distinct upper mantle high‐velocity anomalies are imaged throughout the continent and suggest multiple cratonic roots within the Congo region and possible cratonic roots within the Sahara Metacraton.

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Section: 1029/2018gc007804mentioning

confidence: 99%

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Emry

Shen

Nyblade

et al. 2019

Geochem Geophys Geosyst

152

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“…We use an array of 182 seismic stations deployed during 1997-2015 in the Afar depression, MER and surrounding plateaux in Ethiopia but also stations in Djibouti, Eritrea, and Yemen. Data are sourced from different projects including the Ethiopian Afar Geoscientific Lithospheric Experiment (EAGLE) deployment in 2001-2003 (e.g., Bastow et al, 2005;Keir et al, 2006;Stuart et al, 2006), the Afar Consortium project in 2007(e.g., Hammond et al, 2011Belachew et al, 2011), the Geoscope station ATD in Djibouti in 1993-2010 (e.g., Debayle et al, 2001;Sicilia et al, 2008), a temporary Eritrean deployment in 2011-2012 (e.g., Hammond et al, 2013;Goitom et al, 2015), the YOCMAL project in Yemen in 2009-2011 (Ahmed et al, 2013;Korostelev et al, 2014Korostelev et al, , 2015, and a French deployment in Djibouti in 2009-2011 ( Figure 1).…”

Section: Datamentioning

confidence: 99%

Imaging Lithospheric Discontinuities Beneath the Northern East African Rift Using S‐to‐P Receiver Functions

Lavayssière

Rychert

Harmon

et al. 2018

Geochem Geophys Geosyst

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Imaging the lithosphere is key to understand mechanisms of extension as rifting progresses. Continental rifting results in a combination of mechanical stretching and thinning of the lithosphere, decompression upwelling, heating, sometimes partial melting of the asthenosphere, and potentially partial melting of the mantle lithosphere. The northern East African Rift system is an ideal locale to study these processes as it exposes the transition from tectonically active continental rifting to incipient seafloor spreading. Here we use S‐to‐P receiver functions to image the lithospheric structure beneath the northernmost East African Rift system where it forms a triple junction between the Main Ethiopian rift, the Red Sea rift, and the Gulf of Aden rift. We image the Moho at 31 ± 6 km beneath the Ethiopian plateau. The crust is 28 ± 3 km thick beneath the Main Ethiopian rift and thins to 23 ± 2 km in northern Afar. We identify a negative phase, a velocity decrease with depth, at 67 ± 3 km depth beneath the Ethiopian plateau, likely associated with the lithosphere‐asthenosphere boundary (LAB), and a lack of a LAB phase beneath the rift. Using observations and waveform modeling, we show that the LAB phase beneath the plateau is likely defined by a small amount of partial melt. The lack of a LAB phase beneath the rift suggests melt percolation through the base of the lithosphere beneath the northernmost East African Rift system.

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“…The fast polarization direction of shear wave splitting for teleseismic SKS waves has a roughly north-south orientation across the shield [Wolfe et al, 1999;Hansen et al, 2006;Elsheikh et al, 2014] indicating strong lattice preferred alignment due to north-directed shearing deformation. Some studies also investigated the seismic structure beneath Cenozoic volcanic region and margin of the Arabian plate [e.g., Koulakov and Sobolev, 2006;Korostelev et al, 2014Korostelev et al, , 2015Koulakov et al, 2015] and find evidence for dike intrusions within the crust.…”

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confidence: 99%

Upper mantle velocity structure beneath the Arabian shield from Rayleigh surface wave tomography and its implications

Yao

Mooney

Zahran³

et al. 2017

JGR Solid Earth

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We measured phase velocities at 13 periods from 20 s to 143 s using Rayleigh wave data recorded at recently installed, dense (135) broadband seismic stations in the Arabian shield and determined the shear‐wave velocity structure. Our results clearly reveal a 300 km wide upper mantle seismic low‐velocity zone (LVZ) beneath the western Arabian shield at a depth of 60 km and with a thickness of 130 km. The LVZ has a north‐south trend and follows the late‐Cenozoic volcanic areas. The lithosphere beneath the western Arabian shield is remarkably thin (60–90 km). The 130 km thick mantle LVZ does not appear beneath the western Red Sea and the spreading axis. Thus, the Red Sea at 20°–26°N is an asymmetric rift, with thin lithosphere located east of the Red Sea axis, as predicted by the low‐angle detachment model for rift development. Passive rifting at the Red Sea and extensional stresses in the shield are probably driven by slab pull from the Zagros subduction zone. The low shear‐wave velocity (4.0–4.2 km/s) and the geometry of LVZ beneath the western shield indicate northward flow of hot asthenosphere from the Afar hot spot. The upwelling of basaltic melt in fractures or zones of localized lithospheric thinning has produced extensive late Cenozoic volcanism on the western edge of the shield, and the buoyant LVZ has caused pronounced topography uplift there. Thus, the evolution of the Red Sea and the Arabian shield is driven by subduction of the Arabian plate along its northeastern boundary.

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Upper mantle structure of the southern Arabian margin: Insights from teleseismic tomography

Cited by 11 publications

References 83 publications

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Imaging Lithospheric Discontinuities Beneath the Northern East African Rift Using S‐to‐P Receiver Functions

Upper mantle velocity structure beneath the Arabian shield from Rayleigh surface wave tomography and its implications

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