A common deep source for upper-mantle upwellings below the Ibero-western Maghreb region from teleseismic P-wave travel-time tomography

Civiero, Chiara and Strak, Vincent and Custódio, Susana and Silveira, Graça and Rawlinson, Nicholas and Arroucau, Pierre and Corela, Carlos (2018) A common deep source for upper-mantle upwellings below the Ibero-western Maghreb region from teleseismic P-wave travel-time tomography. Earth and Planetary Science Letters, 499. pp. 157-172. ISSN 0012-821X DOI https://doi.org/10.1016/j.epsl.2018.07.024

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Abstract

Upper-mantle upwellings are often invoked as the cause of Cenozoic volcanism in the Ibero-western Maghreb region. However, their nature, geometry and origin are unclear. This study takes advantage of dense seismic networks, which cover an area extending from the Pyrenees in the north to the Canaries in the south, to provide a new high-resolution P-wave velocity model of the upper-mantle and topmost lower-mantle structure. Our images show three subvertical upper-mantle upwellings below the Canaries, the Atlas Ranges and the Gibraltar Arc, which appear to be rooted beneath the upper-mantle transition zone (MTZ). Two other mantle upwellings beneath the eastern Rif and eastern Betics surround the Gibraltar subduction zone. We propose a new geodynamic model in which narrow upper-mantle upwellings below the Canaries, the Atlas Ranges and the Gibraltar Arc rise from a laterally-propagating layer of material below the MTZ, which in turn is fed by a common deep source below the Canaries. In the Gibraltar region, the deeply rooted upwelling interacts with the Gibraltar slab. Quasi-toroidal flow driven by slab rollback induces the hot mantle material to flow around the slab, creating the two low-velocity anomalies below the eastern Betics and eastern Rif. Our results suggest that the Central Atlantic plume is a likely source of hot mantle material for upper-mantle upwellings in the Ibero-western Maghreb region.

Item Type:	Article
Uncontrolled Keywords:	2018AREP; IA73
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access
Journal or Publication Title:	Earth and Planetary Science Letters
Volume:	499
Page Range:	pp. 157-172
Identification Number:	https://doi.org/10.1016/j.epsl.2018.07.024
Depositing User:	Sarah Humbert
Date Deposited:	03 Sep 2018 10:26
Last Modified:	12 Sep 2019 09:41
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4317

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