Exploring the Passive Margins-a case study from the Eastern Continental Margin of India

The Eastern Continental Margin of India (ECMI) is a passive margin, evolved due to the break-up of India from East Antarctica during Late Cretaceous (140-120 Ma). Over the last three decades extensive marine geophysical data (bathymetry, magnetic, gravity and multi-channel seismic reflection) was collected over the ECMI. These data sets were analyzed to understand the structure, tectonics and the geodynamic evolution of this passive margin. This paper presents the synthesis of the results obtained from marine geophysical studies spanning over a period of nearly two decades, mainly related to the geomorphology, tectonics, coastal seismicity, Holocene sea level history and marine geohazards of the margin. The geodynamic evolution of this passive margin is explained based on the major tectonic lineaments like Continent-Ocean Boundary (COB), the NE-SW horst and graben trend of the continental basement and the rift related dyke intrusions within the continental basement. Land - Ocean Tectonic lineaments (LOTs) identified from the data reveal neotectonic activity associated at the three locations over the ECM'. Holocene sea level history has been traced from the high resolution seismic reflection data. Marine geohazards over the basinal and non basinal areas of ECMI have been demarcated. Scope for future studies is also discussed.