Asymmetry in Bouguer gravity anomalies over the northern and southern parts of India: Some geodynamical aspects

A significant asymmetry is seen in the Bouguer gravity anomalies across the northern and southern parts of the Indian subcontinent. Southern side has relatively very low gravity anomalies while quite high Bouguer gravity values are observed over the northern part. This asymmetry could arise due to (i) underplating of high-density material in the deep crust beneath various mobile belts that exist in the northern part of India, and (ii) thermally induced positive buoyancy and low density of the crust-mantle beneath the southern cratons. It is shown here that the interaction of the the mantle plumes with the overlying continental lithosphere, significantly modified the underlying crust-mantle structure (Raval, 1989; Fyfe, 1993) which in turn, resulted into contrasting gravity field over the northern and southern parts of Indian subcontinent. It is noted that similar contrasts also exist in some other geological and geophysical parameters associated with this continent.