Archaean Cratons in Central, Eastern and Western India

Abstract

The central, eastern and western parts of the Indian Shield comprise, respectively, the Bastar, the Singhbhum and the Bundelkhand cratons. These three cratons of Archaean antiquity are separated one from the other by Proterozoic mobile belts (Fig. 3.1). The Proterozoic mobile belts have gone through cycles of deformation, metamorphism and granite emplacement. They are bounded by shear zones and thrusts of considerable consequence. In common with the Dharwar Craton in the southern part of the Indian Shield, the early crustal development in these cratonic provinces took place around the nuclei of Palaeoarchaean rocks, and the process of cratonization was completed by the end of the Neoarchaean about 2600–2500 million years ago. The evolution of the Archaean cratons entailed stretching and rifting of sialic crust. This was followed by basic volcanism and attendant intrusion of basic–ultrabasic plutons. After that there was sedimentation in tectonically formed intracratonic linear basins. Finally, there was granite emplacement took place on extensive scales. The granitic magmas that were emplaced 2600–2500 Ma ago represent the finale of the tangled history of the Archaean era in the Indian Shield.