Variscan multistage granitoid magmatism in Brunovistulicum: petrological and SHRIMP U-Pb zircon geochronological evidence from the southern part of the Strzelin Massif, SW Poland

摘要

U-Pb SHRIMP ages of one granodiorite and two tonalite samples from the Strzelin Massif, northern part of Brunovistulicum, reveal three distinct stages of Carboniferrous–early Permian granitoid magmatism: tonalitic I-324 Ma, granodioritic – 305 Ma and tonalitic II/gra-nitic – 295 Ma. The first stage of magmatism coincided with the first migmatization event which took place shortly after the first defor-mation. The second stage of granitoid plutonism was coeval with the second migmatization event which produced abundant pegmatites. It took place after compressional phases of the second deformation and was related to decompression at the beginning of tectonic denuda-tion. The third, most abundant stage of magmatism was connected with tate extension in that part of the Variscan Orogen.