Some geodynamic complexities related to the evolution of Bengal Fan and the neotectonic activity of the south Indian shield

After three decades of the International Indian Ocean Expedition (IIOE) and in spite of extensive geophysical data collected during the last one decade, the geodynamics of the Bengal Fan and the Peninsular shield at the northern end of the Indian Plate remains complex and unresolved. Though recent analysis of few multichannel seismic sections from the Central Bengal Fan could resolve some of the ambiguities, views still differ on several aspects such as the nature and age of the oceanic crust, trends of fracture zones, origin and age of the hotspot traces in relation to the break up and drift of the Indian Plate. Recent inferences on the deformation from Peninsular shield have introduced further complications on the tectonics of the region and suggest a mosaic of east-west and north-south lithospheric upwarps beneath the south Indian shield.