A synthesis of the petrological characters of granulite facies rocks that contain equilibrium sapphirine t quartz assemblage from two localities(Tonagh Island(TI)and Priestley Peak(PP))in the Napier Complex,East Antarctica,provides unequivocal evidence for extreme crustal metamorphism possibly associated with the collisional orogeny during Neoarchean.The reaction microstructures associated with sapphirine t quartz vary among the samples,probably suggesting different tectonic conditions during the metamorphic evolution.Sapphirine and quartz in TI sample were probably in equilibrium at the peak stage,but now separated by corona of Grt + Sil + Opx suggesting near isobaric cooling after the peak metamorphism,whereas the Spr + Qtz + Sil + Crd + Spl assemblage replaces garnet in PP sample suggesting post-peak decompression.The application of mineral equilibrium modeling in NCKFMASHTO system demonstrated that Spr + Qtz stability is lowered down to 930℃ due to small Fe3+contents in the rocks(mole Fe2O3/(FeO + Fe2O3)0.02).The TI sample yields a peak p-T range of 950e1100 C and 7.5e11 kbar,followed by cooling toward a retrograde stage of 800e950 C and 8e10 kbar,possibly along a counterclockwise p-T path.In contrast,the peak condition of the PP sample shows 1000e1050 C and>12 kbar,which was followed by the formation of Spr + Qtz corona around garnet at 930e970 C and 6.7e7.7 kbar,suggesting decompression possibly along a clockwise p-T trajectory.Such contrasting p-T paths are consistent with a recent model on the structural framework of the Napier Complex that correlates the two areas to different crustal blocks.The different p-T paths obtained from the two localities might refect the difference in the tectonic framework of these rocks within a complex Neoarchean subduction/collision belt. A synthesis of the petrological characters of granulite facies rocks that contain equilibrium sapphirine t quartz assemblage from two localities (Tonagh Island (TI) and Priestley Peak (PP)) in the Napier Complex, East Antarctica, provides unequivocal evidence for extreme crustal metamorphism possibly associated with the collisional orogeny during Neoarchean the reaction microstructures associated with sapphirine t quartz vary among the samples, probably suggesting different tectonic conditions during the metamorphic evolution. Apphirine and quartz in TI sample were probably in equilibrium at the peak stage, but now separated by corona of Grt + Sil + Opx suggesting near isobaric cooling after the peak metamorphism, while the Spr + Qtz + Sil + Crd + Spl assemblage replaces garnet in PP sample suggesting post-peak decompression. The application of mineral equilibrium modeling in NCKFMASHTO system prototype that Spr + Qtz stability is going down to 930 ℃ due to small Fe3 + contents in the rocks (mole Fe2O3 / (FeO + Fe2O3) 0.02). The TI sample yields a peak pT range of 950e1100C and 7.5e11 kbar, followed by cooling toward a retrograde stage of 800e950C and 8e10 kbar, possibly along a counterclockwise pT path. contrast, the peak condition of the PP sample shows 1000e1050 C and> 12 kbar, which was followed by the formation of Spr + Qtz corona around garnet at 930e970 C and 6.7e7.7 kbar, suggesting Decompression along a clockwise pT trajectory. Such contrasting pT paths are consistent with a recent model on the structural framework of the Napier Complex that correlates the two areas to different crustal blocks. the different pT paths obtained from the two localities might refect the difference in the tectonic framework of these rocks within a complex Neoarchean subduction / collision belt.