Gravity anomalies, sediment loading and lithospheric flexure associated with the Krishna–Godavari basin, eastern continental margin of India

Abstract

Gravity anomalies constrained by seismic data have been used to examine the long-term mechanical properties of the lithosphere beneath the Krishna–Godavari basin, a deltaic sedimentary basin on the eastern continental margin of India. The gravity effect of the rift crust, sedimentary loading and erosional unloading have been computed and the sum effect of these, when compared with the observed gravity anomalies, gives a best fitting Te of 30 km at the margin. The results suggest that the lithosphere, which was weak during the early rifting-stage, has gained strength during sedimentation. The onshore dipping doublet gravity anomaly at the margin reflects a weak rifted continental lithosphere abutting a strong oceanic lithosphere. Comparison with the results of similar investigations for the Bengal basin in the north and Cauvery basin in the south suggests increasing strength for the lithosphere from north to south.