Tectonothermal events in Central Indian Tectonic Zone (CITZ) and its implications in Rodinian crustal assembly

Abstract

The Precambrian crust of Central India comprising Bundelkhand Craton (BKC) in the north and Bastar Craton (BC) in the south were accreted along a ENE–WSW trending Proterozoic Central Indian Tectonic Zone (CITZ). The CITZ is an ensemble of several low- to medium-grade supracrustal belts, gneisses, granitoids and a few linear tracts of granulite belts. A number of crustal scale shear zones define the boundaries of the supracrustal belts and discrete terrains. Available data suggest polyphase tectonothermal events in CITZ, spanning from Palaeoproterozoic to early Neoproterozoic. Each event is characterized by contractional tectonic regime and attendant metamorphism and magmatism. A new plate tectonic model, in contrast to the earlier one of Yedekar et al. [Geol. Surv. India Spec. Publ. 28 (1990) ], is proposed. According to the present model a northward dipping subduction system leading to continent–continent collision explains the growth and assembly of the CITZ. The continent–continent collision is tentatively placed at ca. 1.5 Ga, which is comparable to similar tectonothermal event in Chotanagpur Gneissic Complex further east. While the suturing event predates the global Grenvillian Orogeny (∼ca. 1.3–1.0 Ga), the Sausar tectonothermal event (ca. 1.1–0.9 Ga) of CITZ is correlatable with the latter.