A dynamic lithosphere–asthenosphere boundary near the equatorial Mid-Atlantic Ridge

In plate tectonic theory a weak asthenosphere is required to facilitate the motions of rigid plates. Partial melt could weaken mantle, in turn impacting convection, but date existence persistent has remained controversial. A wide range scenarios been reported terms location, amount and pathways melt. Here we use data collected by 39 ocean bottom seismometers deployed near equatorial Mid-Atlantic Ridge on 0 80 Myr old seafloor. We calculate S-to-P (Sp) receiver functions perform waveform modeling. jointly interpret with shear-wave velocity tomography from surface waves magnetotelluric (MT) imaging take advantage resolutions sensitivities illuminate structure oceanic lithosphere underlying asthenosphere. image thickness that increases age one location undulates another location. infer thin slightly thicker channels punctuated regions ascending partial several hundred kilometers off ridge axis. This suggests persists over geologic timescales, although its character dynamic, implications for lithosphere–asthenosphere boundary (LAB) driving forces Ascending intermittently feeds at base plate. The associated melt-enhanced buoyancy influence ridge-push motions, whereas channelized reduces resistance plates motion. Therefore, dynamics may play larger role controlling tectonics than previously thought.