Flow of Canary mantle plume material through a subcontinental lithospheric corridor beneath Africa to the Mediterranean: REPLY

Abstract

We present geochemical data of lavas from northwest Africa, allowing us for the fi rst time to carry out large-scale "mapping" of sublithospheric mantle fl ow beneath the northwest African plate. Our study indicates that Canary mantle plume material traveled laterally along a subcontinental lithospheric corridor (i.e., at depths that are usually occupied by continental lithospheric mantle) more than 1500 km to the western Mediterranean, marking its route over the last 15 m.y. through a trail of intraplate volcanism. A three-dimensional geodynamic reconstruction, integrating results from geophysical studies, illustrates that long-distance lateral fl ow of mantle material into and through a subcontinental lithospheric corridor can be caused by a combination of (1) defl ection of upwelling plume material along the base of the lithosphere, (2) delamination of subcontinental mantle lithosphere beneath northwest Africa, and (3) subduction suction related to the rollback of the subducting oceanic plate in the western Mediterranean. Although the fl ow of plume material beneath oceanic lithosphere to mid-ocean ridges or along the base of continental rifts has been previously shown, this study demonstrates that plume material can also fl ow large lateral distances through subcontinental corridors from suboceanic to nonrifting subcontinental settings, generating continental intraplate volcanism without the need for a plume to be located directly beneath the continent.

The Atlas of Morocco: A Plume‐Assisted Orogeny

“…This slab retreat would have produced toroidal flow that entered through the slab window (Diaz, Gallart, & Carbonell, 2016;Funiciello et al, 2006;Miller et al, 2015). As proposed, this mantle suction involved a broad region influencing the Canary mantle plume that since the late Miocene has started to flow northeastward (Duggen et al, 2009;Mériaux et al, 2015). This hot material, in turn, induced widespread volcanic activity from the late Miocene as documented in previous work and our compilation (see references in Supporting Information S1).…”

“…The isotopic composition of the Anti-Atlas magmas, close to the FOZO (FOcal ZOne) mantle end-member, is typical of the North African Cenozoic alkaline volcanic provinces, including the Moroccan Middle Atlas (Bosch et al, 2014;Duggen et al, 2009), the Algerian Hoggar (Aït-Hamou et al, 2000;Allègre et al, 1981;Maza et al, 1998), the Northeastern African volcanism (Sudan and Egypt; Lucassen et al, 2008, the Canary, Lustrino & Wilson, 2007, and the Cape Verde islands (GEOROC database; "https:// georoc.eu").…”

“…This model is also supported by seismic data showing a deep, low-velocity anomaly at shallow upper mantle depths (Miller et al, 2015;Sun et al, 2014) and deeply rooted beneath the Canary Islands (Civiero et al, 2018(Civiero et al, , 2020 from the upper mantle transition zone. In particular, Duggen et al (2009) proposed that a hot upwelling rising from the Canarias plume may be able to flow over large distances beneath the Atlas due to mantle suction produced by slab retreat and subsequent peeling/delamination in the Mediterranean (Mériaux et al, 2015).…”

“…Figure 6. (Sr-Nd-Pb isotopes)-(a) Sr-Nd and (b) Pb isotopic composition of anorogenic volcanism from the Saghro(Berger et al, 2014), Middle Atlas(Duggen et al, 2009;El Azzouzi et al, 2010) and Rif(Duggen et al, 2005;El Azzouzi et al, 1999 volcanic occurrences. The isotopic composition of Canary Islands volcanism derived from Georoc (http://georoc.mpch-mainz.gwdg.de/georoc/) is also reported for comparison.…”

“…Different models have been proposed for the origin of the high topography and volcanism, suggesting a mantle upwelling related to the Canary plume, which originates ∼1,000 km southwest of the Atlas system (Civiero et al, 2018;Duggen et al, 2009), lithospheric thinning by delamination-peel back lithosphere, viscous dripping, plume-like mantle upwelling (Missenard et al, 2006;Ramdani, 1998;Zeyen et al, 2005), or edge driven convection (Missenard & Cadoux, 2012), but the linkage between crustal shortening (including inherited structures), volcanism, and lithospheric thinning/mantle upwelling, and their timing has not been hitherto addressed.…”