A tree of Indo-African mantle plumes imaged by seismic tomography

Mantle plumes were conceived as thin, vertical conduits in which buoyant, hot rock from the lowermost mantle rises to Earth’s surface, manifesting hotspot-type volcanism far plate boundaries. Spatially correlated with hotspots are two vast provinces of slow seismic wave propagation mantle, probably representing heat reservoirs that feed plumes. Imaging plume has proved difficult because most located beneath non-instrumented oceans, and they may be thin. Here we combine new seismological datasets resolve upwelling across all depths length scales, centred on Africa Indian Southern oceans. Using waves sample deepest extensively, show upwellings arranged a tree-like structure. From central, compact trunk below ~1,500 km depth, three branches tilt outwards up towards various Indo-Austral hotspots. We propose each tilting branch represents an alignment vertically rising blobs or proto-plumes, detached linear staggered sequence their underlying low-velocity corridor at core–mantle boundary. Once blob reaches viscosity discontinuity between lower upper it spawns ‘classical’ plume-head/plume-tail sequence. Indo-African structure, might reflect detachment proto-plumes according tomographic imaging.