The Southern Granulite Terrane: A synopsis

The Southern Granulite Terrane (SGT), the wedge-shaped southern termination of Peninsular India, is a mosaic of several crustal blocks and intervening collisional sutures/shears which developed through multiple orogenic cycles during Mesoarchean to late Neoproterozoic-Cambrian. The SGT has been the focus of global geoscience world for more than four decades mainly with regard to deep crustal processes, crustmantle architecture, polyphase structural evolution, extreme crustal metamorphism, growth and recycling of continental crust, and the assembly-evolution-disruption of supercontinents through time, among other aspects. The earliest felsic crust in the SGT includes the 3.5-Ga granitoids in the Coorg Block, .followed by successive maturation stages marked by younger magmatic phases in the various blocks. The zircon delta O-18 values from the Coorg Block also fingerprint the emergence of continental crust above sea level in the early Earth. Multiple arc-magmatic pulses along the margins of the different crustal blocks of the SGT during Neoarchean and Neoproterozoic, together with accreted remnants of ophiolites and other oceanic components, suprasubduction zone complexes, and exhumed high- to ultrahigh-temperature metamorphic orogens suggest subduction-accretion-collision tectonics that constructed the various crustal blocks through time, and incorporated them within Precambrian supercontinent assemblies.