EVENT STRATIGRAPHY AND PHYSICOCHEMICAL CHARACTERS OF BANDED GNEISSIC COMPLEX AND ASSOCIATED SUPRACRUSTALS IN THE SOUTH MEWAR PLAINS OF RAJASTHAN

The oldest cratonic nucleus of the western Indian shield, familiarly k nown as the Banded Gneissic Complex (BGC), occupies a large tract in t he Mewar plains of South Rajasthan. It has essentially an old gneissic component (3.3 Ga) and a host of mafic bodies associated with detrita l and chemogenic sediments which have been subjected to multiple phase s of anatexis and granite intrusions (2.9 Ga and later events). The em placement of Berach granite and succeeding dolerite dyke swarms mark t he end-Archaean cratonization process. This also initiated intracraton ic and cratonmarginal basin formation. Later magmatism, especially alo ng the basement-cover interface, is due to local remobilisation of the basement at the time of Proterozoic orogeny.