A Complex Mantle Plume Head Below East Africa-Arabia Shaped by the Lithosphere-Asthenosphere Boundary Topography

Hot plumes rising from Earth's deep mantle are thought to cause uplift, rifting and large igneous province (LIP) emplacement. LIP volcanism in continents often spans tens of Ma and scatters unevenly over broad areas. This has been attributed to lateral flow of hot plume material, but observational evidence on such flow is scarce. New waveform tomography with massive data sets reveals detailed seismic velocity structure beneath the East Africa-Arabia region, where these processes occur at present. It shows interconnected sub-lithospheric corridors of hot, partially molten rock, fed by three mantle upwellings beneath Kenya, Afar, and Levant. The spatio-temporal distribution of the volcanism suggests that we are witnessing an integral plume head, which morphed into a three-pointed star by ponding and channeling within thin-lithosphere corridors. Plate reconstructions indicate that it spread south-to-north since ∼45 Ma. These results suggest that complex-shape plume heads can explain the enigmatic, scattered LIP volcanism and are, probably, an inherent feature of plume-continent interaction.