New Ideas about the Structure and Nature of the Crust of the Western Part of the Bay of Bengal, Obtained taking into Account Deep Seismic Data

A comprehensive analysis of geological and geophysical data characterizing the structure of the eastern continental margin of India and the adjacent part of the bottom of the Bay of Bengal has been carried out. According to the structural and tectonic features, three sectors are distinguished: southern, central and northern, the natural boundaries between which are the fault zones of the aulacogens Makhanadi and Godavari-Krishna. In the central sector, the pericontinental East Indian Plateau adjoins the continental slope. In 2003, R/V Mezen acquired data using deep seismic sounding method on two profiles in this region. The obtained data and their geological interpretation made it possible to identify the “reduced” continental crust. It is characterized by reduced thickness of the upper, middle and lower layers. A conclusion is made about the continental nature of the East Indian Plateau and the northern part of the Ridge 85° adjacent to it. The light sialic and effusive rocks that form the top of the ridge give a negative gravimetric anomaly in Fay's reduction, which is its outstanding feature.