Superposed folding, transposed fabric growth in granulite facies condition: Implications for possible hiatus in structural history in a granulite complex of the Eastern Ghats belt, India

摘要

The granulite complex around Jenapore, Orissa bears the imprints of three deformations, of which first two (D-1 and D-2) are strong events and related to pervasive deformational fabrics S-1 and S-2 respectively. Sector-wise structural analyses reveal that regional F-1 folds, product of D-1 deformation, are isoclinal, reclined, while the regional F-2 folds, product of D-2 deformation, are upright with overall gentle easterly plunges. Also, the polyclinal and non-cylindrical nature of regional F-2 prior to F-3 folding is evident. This geometrical relation and certain key features such as (1) transposition / cross-cutting of early deformation fabric by later ones; (2) different modes of recrystallization during separate deformation episodes; (3) distinct deformational regime and response of materials related to deformation fabrics and (4) recrystallization of early fabric to a new one under granulite facies condition, definitely indicate a hiatus between D-1 and D-2 deformations.