Bouguer Gravity Modelling of Kaladgi-Badami Basin, Karnataka

The Cuddapah, Kaladgi and Bhima basins have generated renewed interest in the recent past among the petroleum geologists for possible hydrocarbons in Proterozoic environment. As regards the Kaladgi basin, besides favourable structural settings such as a series of plunging anticlines and synclines, buried domal structures and thick columns of sedimentary formations, optimism for possible success stems from the surface gas seepage and gas shows in drilled wells in coeval Vindhyan Basin in Rewa and recent discovery in Shahdol near Jabalpur in the Narmada basin in India and oil fields in equivalent formations in Amadeus basin of Australia, Sichauan and Bohai bay of China and Lena- Tunguska basin of Siberia.

It is therefore tempting to apply the new finite element technique to compute the regional and residual gravity fields of the Kaladgi-Badami basin, and to model the residual anomalies with two objectives, first to estimate the sediment thickness, and secondly to know the northern extent of basin under the Deccan Traps. In the first step, the gravity effect of the overlying basalt was removed from the Bouguer gravity data and then the regional-Residual separation was carried out. The resulting residual anomaly was interpreted in terms of basement depths. The maximum depth of the basin is of the order of 36 kilometers which is well comparable to the estimates by geological observations.