摘要
There is a pile of rock blocks which contain corundum+spinel+garnet+fibrolite association in the form of lenticular enclaves in khondalite series along the Day Nui Con Voi, northwestern Vietnam. The mineral association is resulted from ultrahigh-temperature metamorphism. Meanwhile, the biotite-garnet thermometer and biotite-plagioclase-garnet-quartz association thermobarometer for the mineral associations during retrogressive metamorphism gave temperature and pressure ranges of 879~917 ℃ and 0.90~0.94 GPa, respectively. The metamorphic P-T path shows that there is an early coeval increase in temperature and pressure and a subsequent rapid increase in temperature before reaching the peak conditions.