Chapter 3 - Framework of Indian Shield: Tectonic Subdivisions

Abstract

Relying on the evidence from Peninsular India, it is possible to trace out the clue to understand Precambrian crustal evolution and the basic framework of this crustal block. The information helps to divide this Precambrian terrane into two major tectonic blocks: Precambrian continental core or Proto-India and the accreted charnockite terranes. The combined Precambrian crustal blocks of Proto-India and the accreted terrains constituted the Indian Shield. The Joins that separate/stich the Protocontinents and the ‘accreted’ terranes are marked by different features, such as fault trace, thrust or ductile shear zone, or Lineaments like Narmada-Son, Godavari, or Mahanadi that follow coal-bearing Gondwana rift basins. It is suggested that the invariable occurrence of Gondwana rift basins along some Joins evolved at the time of Gondwana break-up when there was an abortive attempt to fragment the Indian Shield, resulting in the opening of intracratonic continental basins along pre-existing week zones marked by Joins.