Recognition and Correlation of Erosion Surfaces In and Around the Southern Part of Cuddapah Basin

A study of the morphological features in and around the southern part of the Cuddapah Basin brought to light for the first time the existence of erosion surfaces in this area. Two methods were adopted in an attempt to arrive at quantitative data on these, namely (i) collection of data on summit heights (about 1800 in number) over an area of about 8000 sq. miles and (ii) construction of a large scale laboratory model covering an area of about 13500 sq. miles showing 30 north-south profiles taken from 60 one-inch toposheets. As erosion surfaces usually extend across different geological horizons, the study was made to cover both the southern part of the Cuddapah Basin and the Archaeans to the west and south of it.

On the basis of the above studies substantiated by field observations, it is concluded that there are two major erosion surfaces, one around 3000-2700 feet and the other around 2000-1600 feet above mean sea level in this area both having a gentle inclination due north and north-east. The erosion surfaces seem to have been arched along an east-west axis south of the basin. The two surfaces are correlated with two others already suggested in the former Mysore State. The age of the higher surface is considered to be post-Miocene.