Imprints of early deformation structures, fabric development and mineral growth in the high Mg-Al sapphirine granulites, Eastern Ghats Granulite belt, India

Two types of high Mg-Al sapphirine granulites are noted from the area in and around Paderu, Eastern Ghats Granulite belt, India. One is relatively more mafic, coarse-grained variety with crude internal foliation (type I) and the other is relatively fine-grained, more felsic and migmatitic variety with a prominent foliation (type II). In this granulite belt impress of three phases of folding could be detected, with corresponding fabric development. Enclaves of type I variety are preserved within charnockite in the low strain zone: core of mesoscopic F-2 folds, defined by S-1 streaky gneissic foliation. The crude internal foliation in the enclave, discordant to S-1 of the host, could be pre-S-1. The bands of type II variety together with internal foliation, S-1 define F-2 folds. Thus the high Mg-Al sapphirine granulites preserve the imprints of the early deformational fabric. The mineral growth in them along with this fabric, indicating ultra-high temperature metamorphism is correlatable to this early compressive deformation.