Petrology across a calcareous rock-anorthosite interface from the Chilka Lake Complex, Orissa: implications for neo-proterozoic crustal evolution of the Northern Eastern Ghats Belt

• Main Authors: Sengupta, Pulak, Dasgupta, Somnath, Dutta, Niloy Ranjan, Raith, Michael M.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier Science 2008
• Subjects: QE Geology; Antarctic; Antarc*
• Online Access: http://repository.ias.ac.in/67396/; http://www.sciencedirect.com/science/article/pii/S0301926807002495

Mineral assemblages, reaction textures and consideration of deduced mineral reactions in appropriate petrogenetic grids in calc-silicate rocks occurring at the contact of the 0.79 Ga Chilka Lake anorthosite pluton, northeastern part of the Eastern Ghats Belt, India, reveal UHT-metamorphism (T > 1000 ° C) at mid-crustal depths (corresponding to 7 ± 1 kbar). This 0.79 Ga thermal metamorphism completely erased imprints of an earlier (0.96 Ga) granulite facies metamorphism in the calc-silicate rocks. The anorthosite and UHT contact metamorphic rocks were overprinted by amphibolite-granulite facies tectonothermal re-working at 0.69-0.66 Ga. Both the anorthosite-induced UHT metamorphism and the high-grade Pan-African re-working are unique for the Eastern Ghats Belt. These new observations provide clues regarding integration and disintegration of Rodinia and Indo-Antarctic correlation in the Precambrian.