Granulite-facies rocks occurring north-east of the Chilka Lake anothosite (Balugan Massif) show a complex metamorphic and deformation history. The M₁$–$D₁ stage is identified only through microscopic study by the presence of S₁ internal foliation shown by the M₁ assemblage sillimanite–quartz–plagioclase–biotite within garnet porphyroblasts of the aluminous granulites and this fabric is obliterated in outcrop to map-scale by subsequent deformations. S₂ fabric was developed at peak metamorphic condition (M₂$–$D₂­) and is shown by gneissic banding present in all lithological units. S₃ fabric was developed due to D₃ deformation and it is tectonically transposed parallel to S₂ regionally except at the hinge zone of the F₃ folds. The transposed S₂/S₃ fabric is the regional characteristic structure of the area. The D₄ event produced open upright F₄ folds, but was weak enough to develop any penetrative foliation in the rocks except few spaced cleavages that developed in the quartzite/garnet–sillimanite gneiss. Petrological data suggest that the $M_{4}–D_{4}$ stage actually witnessed reactivation of the lower crust by late distinct tectonothermal event. Presence of transposed $S_{2}/S_{3}$ fabric within the anorthosite arguably suggests that the pluton was emplaced before or during the $M_{3}–D_{3}$ event. Field-based large-scale structural analyses and microfabric analyses of the granulites reveal that this terrain has been evolved through superposed folding events with two broadly perpendicular compression directions without any conclusive evidence for transpressional tectonics as argued by earlier workers. Tectonothermal history of these granulites spanning in Neoproterozoic time period is dominated by compressional tectonics with associated metamorphism at deep crust.

Megacrystic granitoids associated with migmatitic and metasedimentary gneisses occurring around Nagavalli Shear Zone (NSZ) preserve complex metamorphic and deformation history. Thinly laminated discontinuous banding of quartzofeldspathic layer (S₁) in the migmatites is the product of first incipient melting during prograde M₁–D₁ tectonothermal event. Peak M₂–D₂ event is manifested by the development of S₂ gneissic foliation in all rocks, which is axial planar to rootless folds on S₁.Porphyroblastic garnet mantled by leucosomal melt fraction in granitoids, suggest that the rock suffered peak granulite facies metamorphism along with host migmatitic gneisses. The subsequent D₃ event deforms differently the massive granitoids and the migmatitic granulite gneisses. The D₄ deformation acted as transpression with broad northwest–southeast compression that develops strong discontinuous regional-scale anastomosing shear zones transecting the earlier gneissosity (S₂) in the granitoids with prominent sinistral shear sense. It deforms the axial plane of regional folds in migmatites and develops superposed non-plane non-cylindrical folds in outcrop to regional scale. Thus we infer megacrystic granitoids were possibly emplaced in pre- to syn-peak metamorphic event within the host granulites. Granitoids and associated migmatitic gneisses of Late Meso- to Neoproterozoic age suffered subsequent petrotectonic events followed by a sinistral transpression acted along NSZ.