The petrogenesis and evolution of metamorphic rocks of the volcanoplutonic units of the Kaskama block of the Inari Terrane in northwestern Russia were studied. A petrographic and mineral study and modeling of igneous and metamorphic mineral formation were performed. PT-conditions of rocks, along with previously known data, including geochronological ones, do not allow us to correlate the studied units with rocks of the Belomorian complex, as previously thought. Modeling of igneous and metamorphic mineral shows good convergence with the fields of stability of mineral parageneses and quantitive ratio of minerals with those observed in the real samples. The early mineral parageneses of the magmatic stage corresponds to the crystallization of rock-forming and accessory minerals from the komatiite melt, and mineral parageneses of progressive and regressive metamorphism stages
are superimposed on them. Relic igneous minerals (olivine, clinopyroxene, orthopyroxene, magnetite-spinel) in metaperidotites make it possible to estimate their liquidus temperatures in the range of 1480-950 °С. The progressive stage of metamorphism is characterized by the development of mineral parageneses: garnet + amphibole + plagioclase + quartz ± biotite, amphibole + plagioclase + quartz. The late low-temperature regressive stage of metamorphism is characterized by the development of epidote-, zoisite-, actinolite-containing associations and a
number of other low-temperature minerals. Peak parameters of progressive metamorphism are estimated as Т = 600-700 °С, Р = 5-9 kbar and for the regressive stage as Т = 400-500 °С, Р = 3-5 kbar. The identified thermodynamic conditions for the Kaskama block should be considered when determining whether the studied volcanoplutonic and metasedimentary units belong to the Paleoproterozoic terranes of the Kola-Norwegian Region of the Fennoscandian Shield.