Publication Date:
2021-07-14
Description:
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.
Description:
Published
Description:
1019-1022
Description:
2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
Description:
3.3. Geodinamica e struttura dell'interno della Terra
Description:
3.4. Geomagnetismo
Description:
JCR Journal
Description:
restricted
Keywords:
Red Sea
;
gravity anomaly
;
oceanic crust
;
seafloor spreading
;
Mantle convection
;
Magnetic anomaly
;
04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics
;
04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies
;
04. Solid Earth::04.04. Geology::04.04.04. Marine geology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
