What caused the sudden acceleration of the Indian plate during the Late Cretaceous: Reunion plume or double subduction?

The causal mechanism behind the rapid acceleration of the Indian plate between 67 and 62 Ma remains elusive. The timing of this acceleration is coeval with the Deccan flood basalt eruption. Prior studies have attributed this acceleration to various causes, of which the arrival of the Reunion plume and the Tethyan double subduction are two major ones. In this study, we test these two hypotheses using global mantle convection models incorporating a mix of plate motion history and a free-slip boundary condition. Our results suggest that the effect of the Reunion plume, which includes plume push and lubrication below the lithosphere, can explain the temporal variation of the Indian plate motion ca. 65 Ma. The Tethyan double subduction models predict even higher plate velocities but fail to slow down the plate. A model with a 500 km plume head radius and an asthenosphere viscosity (ηasth) of 5 × 1019 Pa∙s can match the observed temporal variation of the Indian plate motion and predicts a peak melting age of 66 Ma, similar to the peak age of Deccan volcanism.