Dip Ghosh, Joyjeet Sen, Nibir Mandal

In peninsular India, the Deccan Traps record massive, continental-scale volcanism in a sequence of magmatic events that mark the mass extinction at the Cretaceous-Paleogene boundary. Although the Deccan volcanism is linked with the Réunion hotspot, the origin of its periodic magmatic pulses is still debated. We develop a numerical model, replicating the geodynamic scenario of the African superplume underneath a moving Indian plate, to explore the mechanism of magmatic pulse generation during the Deccan volcanism. Our model finds a connection between the Réunion hotspot and the African large low shear-wave velocity province (LLSVP) to show pulse generation from a thermochemical plume in the lower mantle. The plume is perturbed at 660 km, and its head eventually detaches from the tail under the influence of Indian plate movement to produce four major pulses (periodicity: 5 - 8 Ma), each giving rise to multiple secondary magmatic pulses at a time interval of ~ 0.15-0.4 Ma.