Revisiting the scale of mantle plume–induced hot spot swells

Hotspot swells have typically been associated with mantle plume upwelling, yet the origins of much broader but lower superswells remain unclear. This study first reveals that swell width increases while height decreases at younger seafloor ages; it is possible for a single hot spot swell size to approach that of a superswell. Compressible numerical models replicate the observed trend. Modeling results suggest that both hot spot swells and superswells can form from interactions between mantle plumes and oceanic plates. Beneath young seafloors, the lateral redistribution of restitic, hence buoyant and relatively low-viscosity, lower lithospheric mantle due to plume impingement explains the formation of superswell-like morphology. These models effectively demonstrate lithospheric lid effects on mantle melting and support a reassessment of conventional methods for estimating core heat flux.