Event Stratigraphy and Physico-Chemical Characters of Banded Gneissic Complex and Associated Supracrustals in the South Mewar Plains of Rajasthan

The oldest cratonic nucleus pf the Western Indian shield, familiarly known as the Banded Gneissic Complex (BGC), occupies a large tract in the Mcwar plains of South Rajasthan. It has essentially an old gneissic component (3.3 Ga) and a host of mafic bodies associated with detrital and chemogenic sediments which have been subjected to multiple phases of anatexis and granite intrusions (2.9 Ga and later events). The emplacement of Berach granite and succeeding dolerite dyke swarms mark the end-Archaean cratonization process. This also initiated intracratonic and cratonmarginal basin formation.

Later magmatism, especially along the basement-cover interface. is due to local remobilisation of the basement at the time of Proterozoic orogeny.