Constraints on P-T conditions of high-grade metamorphism in the Góry Sowie Mts, West Sudetes

P-T conditions of metamorphism that affected the Góry Sowie Mts gneisses (West Sudetes,SW Poland) were determined with use of garnet-biotite (GB) and muscovite-biotite (MB) geothermometry,and muscovite geobarometry on selected rocks. Granulite and sillimanite-bearing layered gneiss from theBystrzyckie Lake region (northern part of the Góry Sowie Mts) revealed GB temperatures 652 ± 35C. Tothe south, layered gneiss and metapegmatite from the Przygórze area yielded similar GB temperatures(660 ± 28C), lower MB temperatures (613 ± 25C) and pressures 6.4 ± 1.4 kbar. In the central part of themassif, finely laminated gneiss and diatexite from the Potoczek region revealed MB temperatures 596 ± 24Cand pressures 5.2 ± 0.7 kbar. A similar temperature (600 ± 25C) was obtained out of a flaser gneiss from theKietlice region in the Fore-Sudetic part of the Góry Sowie Block. Differences between GB and MB resultsmight be related to different speed of ion diffusion between coexisting minerals. We suggest that reporteddata are related to initial midcrustal exhumation and coeval amphibolite facies metamorphism.