Tectonics of the Bay of Bengal: New insights from satellite-gravity and ship-borne geophysical data

Abstract

Recently released satellite-derived free air gravity anomalies and the existing ship-board geophysical data provide new insights into the tectonics of the Bay of Bengal with respect to the structure and regional extension of the buried 85 degrees E ridge and the tectonics of the Eastern Continental Margin of India (ECMI). The 85 degrees E ridge can be visualized extending inland via the Mahanadi basin volcanics to the Rajmahal Traps. A large volcanic province in eastern India encompassing the Rajmahal and Sylhet Traps and volcanics in the Bengal and Mahanadi basins, almost on the scale of the Deccan volcanic province along the west coast, can be envisaged taking into account the occurrences of intrusive rocks around the age of 117 Ma. Gravity models of the ridge are indicative of hotspot-related crustal underplating processes beneath the ridge. The ECMI can be divided into a southern transform and northern rifted segments on the basis of gravity and bathymetry data, which bear similarities with the conjugate East Antarctica margin