A two-stage evolution of Visakhapatnam-Paradip Shelf, east coast of India, from magnetic studies

Abstract

A detailed analysis of bathymetry and magnetic data of Visakhapatnam-Paradip shelf, east coast of India revealed three major structural lineaments over the shelf/slope of the area. Models derived from the anomalies associated with the trends indicate that trend. A represents horst and graben type continental basement while trend B is due to a series of dyke intrusions. Trend C off Chilka Lake forms the northward extension of 85 degrees E lineation from deep sea Bengal Fan. A two stage evolution of the eastern continental margin of India has been inferred from the study of this part of the margin, viz, the rift stage evidenced by dyke intrusions of reverse polarity located within the inner part of the shelf and post-rift stage characterized by vertical lectonics in the form of a horst and graben type continental basement. The hotspot related aseismic 85 degrees E ridge further complicated the tectonics of this part of the area