R8: Metamorphic rocks and tectonics

[R8-11] Counterclockwise and clockwise P-T histories recorded in a single sample? (Brattnipene, Sør Rondane Mountains, East Antarctica)

*Hayato Ikeda¹, Tetsuo Kawakami¹, Fumiko Higashino¹ (1. Kyoto Uni. Sci.)

Keywords:continental collision, granulite, Zr-in-rutile geothermometry, trace element

Temperature-pressure (P-T) path of a Grt-Sil-Bt gneiss from Brattnipene, Sør Rondane Mountains, East Antarctica was constrained. Grt A in Pl-dominated layers probably broke down to Bt+Pl+Ky+Sil+Qz+Rt at 770^oC, 0.9 GPa during cooling. Grt B in Grt+Bt-dominated layers is estimated to have formed at 750-850^oC, 0.5-0.7 GPa, followed by isothermal decompression and cooling. P-T histories indicative of clockwise and counterclockwise (or isobaric cooling) paths are both found in a single sample.