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Based on detailed studies on the compositional zoning of garnet and biotite in pelitic rocks from the Jingshan group of granulite facies in north Jiaodong, P-T pseudosections with isopleths of Fe/(Fe + Mg) in garnet and biotite were calculated in the KF-MASH system for two representative rocks of sillimanite-garnet-cordierite-biotite gneiss ( Vbi/ Vg>1 ) and sillimanite-garnet gneiss (Vbi/ Vg<0.2) using the software THERMOCALC and the internally consistent thermodynamic dataset. With a comparison of the calculated Fe/(Fe+ Mg) values in garnet and biotite in the peak P-T fields constrained by peak mineral assemblages with the measured ones, it is concluded that the coarse garnet crystals with diffusion zoning from high grade meta-pelites can preserve their peak compositions even when they have experienced a cooling event, and that biotite crystals surrounded by fetsic minerals in biotite-rich rocks with Vbi/Vg> 1 can nearly preserve their peak compositions, and biotites in garnet-rich rocks with Vbi/Vg<0. 2 cannot preserve their peak compositions due to the influence of grain-boundary fluid.
Based on detailed studies on the compositional zoning of garnet and biotite in pelitic rocks from the Jingshan group of granite facies in north Jiaodong, PT pseudosections with isopleths of Fe / (Fe + Mg) in garnet and biotite were calculated in the KF-MASH system for two representative rocks of sillimanite-garnet-cordierite-biotite gneiss (Vbi / Vg> 1) and sillimanite-garnet gneiss (Vbi / Vg <0.2) using the software THERMOCALC and the internally consistent thermodynamic dataset. / (Fe + Mg) values in garnet and biotite in the peak PT fields constrained by peak mineral assemblages with the measured ones, it is concluded that the coarse garnet crystals with diffusion zoning from high grade meta-pelites can preserve their peak compositions even when have experienced a cooling event, and that biotite crystals surrounded by fetsic minerals in biotite-rich rocks with Vbi / Vg> 1 can nearly preserve their peak compositions, and biotites in garnet-rich r ocks with Vbi / Vg <0. 2 can not preserve their peak compositions due to the influence of grain-boundary fluid.