A tectonic model of the Narmada region

Analysis of the reinterpreted results of the seismic refraction and wide-an gle reflection data across Narmada-Son Lineament (NSL) indicates that the u pper crustal features to the east and west of the Barwani-Sukta fault are d ifferent. To the west of this fault a graben exists under the Deccan volcan ics, while to the east of it a north-south horst feature between the Narmad a north and south faults divides the region in three distinct zones - north , middle and south. This feature is accompanied by upwarp in the mid-crusta l as well as the Moho levels, suggesting deep-seated tectonics. The horst c orrelates with the gravity low axis of central India and large thickness of high density mafic material is present in the upper crust on both sides of it. The present-day crustal structure of the Narmada region appears to hav e developed in three major phases of the tectonic activity during the Archa ean-Proterozoic, Jurassic-Cretaceous and late Cretaceous.