The age of the Vindhyan System of Peninsular India

Abstract

New isotopic data, mainly Rb–Sr, are given for the Vindhyan System of Peninsular India, the underlying Gwalior Series and Bijawar Series, and a pipe of kimberlitic affinities which intrudes the Upper Vindhyan. The Vindhyan System is shown to have a base with an age of at least 1200 and possibly 1400 m.y. The Gwalior Series is shown to have an age of between 1600 and 2000 m.y. while the Bijawar Series is very much older at about 2500 m.y. The necessity for revision of palaeomagnetic interpretations based on very different age estimates is shown, and it is recommended that because of its probable long time span any evidence for glaciation in the Vindhyan, at present poor, needs to be carefully attributed stratigraphically.