The Geomorphology of the Vindhyan Plateau, Central India

In Central India, the rocks belong to two groups, Vindhyans of lower Palaeozoic or late Precambrian age and the Deccan Trap lava flows of Cretaceous-Eocene age. The study of the geomorphology has led to the conclusion that after the deposition of the Vindhyans in a shallow inland sea, the country was uplifted. peneplaned and subsequently greatly dissected by a later cycle of erosion. Much later, the old and mature Vindhyan topography was buried beneath the lava flows and the associated sediments.

As denudation proceeded, erosion removed the lavas and sediments in places, laying bare the old land surface beneath. Thus the former topography of mature hills and flat valleys has been resurrected. With the partial removal of the lava flows: the remnants of the Cretaceous peneplain exist at an elevation of about 1950ft. At a lower surface of 1450 ft.,-the lavas rest on a planation surface developed particularly on the weaker rocks in a much more widespread younger cycle. The subvolcanic surface is reconstructed in detail and shows that the current drainage is superimposed on the pre-Deccan trap topography; and after the removal of the lavas, the rivers are tending to revert to the pre-Deccan trap drainage system. The current valley cycle. where the basalts have been removed, is largely coincident with the lower erosion surface, but it is now coming under attack from a newer cycle working up from Narmada and Ganges rivers.