Indo-Antarctic correlation: a perspective from the Eastern Ghats granulite belt, India

Abstract

Available lithological, petrological and geochronological data on the rocks of the Eastern Ghats Belt (EGB), which has a key role to play in any model of Indo-Antarctic correlation in Precambrian and Cambrian times, have been synthesized and interpreted. Longitudinal lithological subdivisions of the belt are mostly not supported by recent geochronological data, which rather suggest a fourfold division based on protolith ages of the ortho- and paragneisses. Mineral ages show prominent tectonothermal events at Mesoproterozoic, Grenvillian and Pan-African times. However, not all of the imprints of all the events are preserved in all the geochronological domains. In the most well-studied Domain II, three phases of metamorphism are recorded -an early ultra high-temperature metamorphism with an anticlockwise P-T path, a second granulite facies event at c. 1000 Ma, with a retrograde trajectory of near-isothermal decompression, and a third of amphibolite facies. The available information, however, is not conclusive as to whether or not the entire EGB experienced polyphase UHT metamorphism. The propagation of the Grenvillian orogenic front in the EGB is identified.