Abstract:The pumpellyite in the eclogites from Uzkaya Salma area of the Belomorian mobile belt, Russia, was formed at the pre-eclogite stage under the condition of sub-greenschist facies. Pumpellyite occurs as inclusions in garnet porphyroblasts and is associated with titanite, rutile, clinopyroxene, chlorite, epidote and quartz. In addition, rare granulous pumpellyite occurs as isolated inclusions in the matrix diopside. According to the composition features of pumpellyite, pumpellyite mostly belongs to pumpellyite-(Al) and rarely belongs to pumpelltie-(Fe). According to the petrographic features and the calculation of phase equilibrium and mineral geothermobarometers, the authors divide the metamorphic evolution of pumpellyite-bearing eclogite into four stages: Stage Ⅰ, which is the pre-peak prograde metamorphic stage characterized by pumpellyite, chlorite, epidote, quartz inclusions within the garnet porphyroblasts, with p-T conditions being t=160~320℃, p=0.2~0.8 GPa according to the stable field of mineral assemblages of pumpellyite + chlorite + quartz and pumpellyite-(Fe) + epidote, based on experimental petrologic study. Stage Ⅱ, the peak eclogite-facies metamorphic stage, which is characterized by the mineral assemblage of garnet + omphacite (the symplectite of diopside and plagioclase) + rutile ± hornblende + quartz; the isopleths in garnet core and the Jd isopleths in omphacite reflect the metamorphic peak condition of 725~740℃ at 1.4~1.5 GPa for the rock. Stage Ⅲ, during which the initial decompressional retrogression began at the high granulite-facies stage characterized by garnet + diopside + hornblende + plagioclase + quartz; the garnet-clinopyroxene thermometer and An isopleths in plagioclase indicate that the p-T conditions t=725~750℃ and p=1.1~1.3 GPa. Stage Ⅳ, which is late retrogression under the condition of amphibolites-facies and is characterized by the mineral assemblage of hornblende+plagioclase±biotite+quartz, with p-T conditions t=670~700℃ and p=0.7~0.9 GPa according to the calculation of phase equilibrium and hornblende-plagioclase thermometer. In conclusion, the pumpellyite-bearing eclogite in Uzkaya Salma area of the Belomorian mobile belt, Russia, shows a clockwise p-T path and the corresponding geothermal gradient in the peak eclogite-facies metamorphic stage is 15℃/km. The initial pre-eclogite metamorphic evolution began under the condition of pumpellyite-epidote facies during subduction. The pumpellyite-bearing eclogite is characterized by isothermal decompression from the peak eclogite-facies to the high granulite-facies. The results obtained by the authors show that "cold" subduction of the plate might have occurred at the early stage of the evolution of the earth during Archean.