Evolution of the East Africa-Arabia plume head

Hot plumes rising from Earth’s deep mantle are thought to form broad plume heads beneath lithospheric plates. In continents, mantle plumes cause uplift, rifting and volcanism, often dispersed over surprisingly broad areas. Using seismic waveform tomography, we image a star-shaped, low-velocity anomaly centered at Afar and composed of three narrow branches: beneath East Africa, beneath the Gulf of Aden, and beneath the Red Sea and West Arabia, extending north to Levant. We interpret this anomaly as the seismic expression of interconnected corridors of hot, partially molten rock beneath the East Africa-Arabia region. The corridors underlie areas of uplift, rifting and volcanism and accommodate an integral, active plume head. Eruption ages and plate reconstructions indicate that it developed south-to-north, and tomography shows it being fed by three deep upwellings beneath Kenya, Afar and Levant. These results demonstrate the complex feedbacks between the continental-lithosphere heterogeneity and plume-head evolution. Star-shaped plume heads sprawling within thin-lithosphere valleys can account for the enigmatic dispersed volcanism in large igneous provinces and are likely to be a basic mechanism of plume-continent interaction.