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

摘要

The granulite complex around Jenapore, Orissa, Eastern Ghats granulite belt, bears the imprint of two episodes of strong deformation (D1 and D2) attended with foliation (fabric) development (S1 and S2). Two distinct metamorphic events at P-T conditions of a??900?° C at a??9 kbar and a??600?° C at a??6 kbar are correlated with D1 and D2 respectively. The reaction textures in S1-microdomains are interpreted to be the product of near isobaric cooling at a??9 kbar from 950?° C to 600?°C, whereas those in the S2-microdomains are considered to be the result of an up-pressure trajectory from a??6 kbar at 600?°C. The D1-M1 high P-T granulite event is interpreted to be Archean in age (ca. 3Ga) 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 D2-S2 is considered to be related to the Grenvillian orogeny as represented by the dominant isotopic record in the belt.