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Saudi Geological Survey, Saudi Arabia
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- PublicationRestrictedInitial burst of oceanic crust accretion in the Red Sea due to edge driven mantle convection(2011-10-04)
; ; ; ; ; ; ; ; ; ; ; ;Ligi, M.; Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche, Bologna ;Bonatti, E.; Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche, Bologna e Lamont Doherty Earth Observatory, Columbia University ;Caratori Tontini, F.; GNS Science, Ocean Exploaration Section, New Zealand ;Cipriani, A.; Lamont Doherty Earth Observatory, Columbia University ;Cocchi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Schettino, A.; Dipartimento di Scienze della Terra, Università di Camerino ;Bortoluzzi, G.; Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche, Bologna ;Ferrante, V.; Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche, Bologna ;Khalil, S.; Department of Geological and Biological Sciences, Suez Canal University, Egypt ;Mitchell, N.; School of Earth, Atmosphere and Environmental Sciences, University of Manchester ;Rasul, N.; Saudi Geological Survey, Saudi Arabia; ; ;; ; ; ; ; ; ; The 500 m.y. cycle whereby continents assemble in a single supercontinent and then fragment and disperse again involves the rupturing of a continent and the birth of a new ocean, with the formation of passive plate margins. This process is well displayed today in the Red Sea, where Arabia is separating from Africa. We carried out geophysical surveys and bottom rock sampling in the two Red Sea northernmost axial segments of initial oceanic crust accretion, Thetis and Nereus. Areal variations of crustal thickness, magnetic intensity, and degree of melting of the subaxial upwelling mantle reveal an initial burst of active oceanic crust generation and rapid seafloor spreading below each cell, occurring as soon as the lid of continental lithosphere breaks. This initial pulse may be caused by edge-driven subrift mantle convection, triggered by a strong horizontal thermal gradient between the cold continental lithosphere and the hot ascending asthenosphere. The thermal gradient weakens as the oceanic rift widens; therefore the initial active pulse fades into steady, more passive crustal accretion, with slower spreading and along axis rift propagation.544 91