Signals of degeneration of the sub-crustal part of the Indian lithosphere since the break-up of Gondwanaland

Currently, the continental fragments of the erstwhile Gondwanaland supercontinent are widely separated. A relative comparison of Magsat anomalies of these fragments reveals a striking similarity across all the rifted continental margins except at the western and southern margins of India. It reflects that magnetized crust has largely remained unchanged elsewhere since the break-up of Gondwanaland. A similar analysis of satellite derived free-air gravity anomalies also indicate a similar continuity across other rifted margins except those of India. These anomalies characterise the existing differences in the crustal and upper-mantle structures and causal dependence on the relative mobilities of the Gondwanic continents. It is evident that after the break-up, only the Indian continental structure has suffered a dramatic change, possibly due to its super northward drift from Antarctica during Late Cretaceous-Early Tertiary.