THE ROLE OF DEEP MANTLE FLOW IN SHAPING THE HAWAIIAN-EMPEROR BEND
The north Pacific features long-lasting subduction systems, unlike those in the south Pacific. We present palaeogeographically-constrained numerical models of thermochemical convection demonstrating that flow in the deep lower mantle under the north Pacific was anomalously vigorous between 100 Ma and 50 Ma. These models show a sharp bend in the Hawaiian-Emperor hotspot track arising from the interplay of plume tilt and the lateral advection of plume sources. We show that the different trajectories of the Hawaiian and Louisville hotspot tracks arise from asymmetric deformation of thermochemical structures under the Pacific between 100 Ma and 50 Ma. This asymmetric deformation waned just before the Hawaiian-Emperor bend developed, owing to flow in the deepest lower mantle associated with slab descent in the north and south Pacific.