Extension of the Intracratonic Mahanadi Rift Towards the East Coast of India - An Inference from Aeromagnetics and Gravity

Interpretation of the total intensity aeromagnetic anomaly data and the residual gravity data of the pericratonic Mahanadi coastal basin, situated in the east coast of India has brought out NW-SE trending dislocations cutting across these basins and extending into the shelf area. This structure may be inferred as the possible extension of the NW-SE trending intracratonic Mahanadi rift. Depth estimates on the regional aeromagnetic anomalies have brought out a deep-seated sub-basement magnetic marker horizon at depths of 5-6 km in the inferred rift zone and it rises to around 2 km on either side in the onshore region. The trends in the residual gravity map around Cuttack suggests a tectonic environment possibly related to the location of triple junction at this point. This zone lies between shot points SF60 and SP70 of the Konark-Mukundpur DSS profile where it is reported that the energy has been heavily attenuated (at near distances) leading to large jumps in travel time. This zone of anomalous behaviour coincides with the inferred triple junction and calls for further detailed studies.