EVOLUTION OF THE CAUVERY BASIN, INDIA FROM SUBSIDENCE MODELING

Backstripping and sediment unloading have been carried out on stratigr aphic data from wells in the various sub-basins of Cauvery Basin to ob tain tectonic subsidence curves. Analysis of the tectonic subsidence c urves reveals that cessation of rifting/extension occurred earlier on the western side and rifting persisted for a longer time on the easter n side. Subsidence was more or less continuous through most of Cretace ous time. A non-uniform (or two-layer) extension model is used to dete rmine extension parameters from the tectonic subsidence curves. The va lues of the crustal (beta) and subcrustal (delta) stretching parameter s obtained in the various sub-basins show the trends of evolution of t he different sub-basins. The analysis suggests that the tectonic subsi dence curves conform more to those in an intracratonic basin than thos e on a passive margin. Geological evidence corroborating this hypothes is are presented, necessitating the classification of Cauvery Basin as an intracratonic failed rift basin as opposed to the earlier classifi cation as a pericratonic basin.