Domainal fabric development, associated microstructures and P-T records attesting to polymetamorphism in a granulite complex of the Eastern Ghats granulite belt, India

The granulite complex around Jenapore, Orissa. Eastern Ghats granulite belt, bear the imprint of two episodes of strong deformation (D-1, and D-2) attended with foliation (fabric) development (S-1 and S-2). Two distinct metamorphic events at P-T conditions of similar to 900 degrees C at similar to 9 kbar and similar to 600 degrees C at similar to 6 kbar are correlated with D-1 and D-2 respectively. The reaction textures in S-1-microdomains are interpreted to be the product of near isobaric cooling at similar to 9 kbar from 950 degrees C to 600 degrees C, whereas those in the S-2-microdomains are considered to be the result of an up-pressure trajectory from similar to 6 kbar at 600 degrees C. The D-1-M-1 high P-T granulite event is interpreted to be Archean in age (ca. 3 Ga) on the basis of the isotopic data obtained from the charnockite suite of the area. The later relatively low P-T granulite facies event, attendant to D-2-S-2 is considered to be related to the Grenvillian orogeny as represented by the dominant isotopic record in the belt.