Model Galena Ages from Karnataka and Surrounding Areas

Lead isotope ratios have been measured for selected samples from the Chitradurga and Kolar schist belts, the high-grade gneisses E of Karnataka (in Tamil Nadu) and Agnigundala of Cuddapahs. Most of the isotope data approximately fit a single-stage model and yield model ages at 3000 m.y., 2500 m.y., 1400 m.y. and 1100 m.y. The relations with other available age data are discussed.