Development of Crustal-Scale Shear Zones at the Singhbhum Craton-Eastern Ghats Belt Boundary Region: A Critical Review of the Mesoarchean-Neoproterozoic Odyssey

A number of crustal-scale shear zones have developed along the southern margin of the Singhbhum Craton, in the boundary with the Neoarchean Rengali Province and the Meso-Neoproterozoic Eastern Ghats Belt. The cratonic part, evolved in a suprasubduction zone setting, bears imprints of late Mesoarchean orogenic episode (D-1C) at ca. 3.1 Ga with folding and thrust imbrication of the cratonic rocks. The succeeding orogenic imprint is etched in the Neoarchean (similar to 2.8 Ga) with development of the Sukinda thrust along the craton margin and thrust-related deformation of the rocks of the Rengali Province (D-2C-D-1R). The latter event remobilized cratonic fringe with development of a spectacular E-W trending transpressional belt in the Southern Iron Ore Group rocks cored by the Sukinda ultramafics. In the Eastern Ghats Belt, the major ultrahigh-temperature orogeny took place during the Grenvillian-age (similar to 1.0-0.9 Ga) assembly of the supercontinent Rodinia. This belt eventually got juxtaposed against the expanded Singhbhum Craton in the end-Neoproterozoic time (similar to 0.5 Ga) along the Kerajang Fault Zone. This latter event remobilized a large part of the Rengali Province (D-2R) with development of an intraterrane transpressional belt bounded by the Barkot Shear Zone in the north. The northern fringe of the intruding Eastern Ghats Belt developed a complex network of strike-slip fault system under this impact, probably an outcome of tectonic activity along the Kuunga suture, which signifies the joining of greater India with East Antarctica. The present synthesis visualizes early development in the craton through formation of a typical orogenic sequence, imbricated in thrust piles, resulting from a ca. 3.1 Ga orogeny. Further cratonic expansion was achieved via repetitive accretion and remobilization, development of crustal-scale faults and transpressional belts at ca. 2.8 Ga and ca. 0.5 Ga, much in a similar fashion as documented along oblique convergent margins of all ages.