A joint geophysical-geochemical deep-mantle zoning map beneath East Africa and the Indian Ocean

Geochemical signatures of hotspot lavas suggest that their mantle sources are compositionally distinct, but their source locations remain elusive. Mapping hotspots to their deep origins is complicated by the presence of interconnected, low-seismic velocity networks in the mantle, where plumelike anomalies often deviate from vertical conduits. We propose a graph theory-based framework to systematically trace ensembles of plume paths using a high-resolution regional tomographic model. Applied to eight East African and Indian Ocean hotspots, our method identified clustered source zones near the core-mantle boundary. Multivariate analysis of the isotope ratios of hotspot-related basalts reveals a broadly similar clustering. Together, these independent observations provide a first-order joint geophysical-geochemical zoning map in this region, with at least three distinct domains within the African large low-shear-velocity province (LLSVP).