Geological features and geophysical signatures of continental margins of India

The shape and classification of continental margins are in general dependent on style of continental splitting, rifting, subsidence and their proximity to the tectonic plate boundaries, at times the margins undergo for modifications by sediment deposition and volcanic activity. Worldwide continental margins are broadly categorized into two groups: passive (Atlantic) and active (Pacific) type margins. The main features of passive continental margin are shelf, slope, rise and abyssal plain. Analyses of marine geophysical data across the eastern and western continental margins of India show that both the margins are different in shape although both belong to passive margin group. While continental slope along the western continental margin is wider and provides scope for multiple picks of foot-of-slope, it narrows along the eastern continental margin and is clear for single pick of foot-of-slope. Continental slope and rise on western margin and rise on eastern margin were modified to a major extent by Deccan-Reunion hotspot volcanism and Bengal Fan sedimentation respectively. Volcanism has dominated on the western continental margin of India, thereby the margin had been turned into a volcanic passive continental margin, while eastern continental margin of India remained as nonvolcanic passive margin.