Late stage Variscan magmatism in the Strzelin Massif (SW Poland): SHRIMP zircon ages of tonalite and Bt-Ms granite of the Gęsiniec intrusion

Teresa Oberc-Dziedzic, Ryszard Kryza
2012 Geological Quarterly  
Teresa OBERC-DZIEDZIC and Ryszard KRYZA Oberc-Dziedzic T. and Kryza R. (2012) -Late stage Variscan magmatism in the Strzelin Mas sif (SW Po land): SHRIMP zir con ages of tonalite and Bt-Ms gran ite of the Gêsiniec in tru sion. Geol. Quart., 56 (2): 225-236, doi: 10.7306/gq.1017 The Gêsiniec com pos ite in tru sion in the north ern part of the Strzelin Mas sif (Fore-Sudetic Block, SW Po land) was formed in the course of three late Variscan mag matic ep i sodes: tonalitic I, granodioritic, and
more » ... alitic II/gra nitic. The age of the Gêsiniec tonalite, 295 ±3 Ma, is the same as that of an other tonalite body in the south ern part of the Strzelin Mas sif, the Kalinka tonalite. The youn ger bi o tite-mus co vite (Bt-Ms) gran ite, in a dyke cut ting the Gêsiniec tonalite, has an in dis tin guish able iso to pic age of 295 ±5 Ma; it con tains, how ever, in herited zir cons with ages be tween ca. 1.5 Ga to 374 Ma, sim i lar to zir con ages from sur round ing gneiss es. This sug gests that the mag matic protolith of gneiss es and the magma of the Bt-Ms gran ite could have come from sim i lar sources, or that the magma of the Bt-Ms gran ite was con tam i nated by the gneiss es. Both the tonalite and Bt-Ma gran ite rep re sent a late stage of the granitoid magmatism in the east ern part of the Variscan orogen. Teresa Oberc-Dziedzic and Ryszard Kryza, In sti tute of Geo log i cal Sci ences, Uni ver sity of Wroc³aw, M.
doi:10.7306/gq.1017 fatcat:qexd2rzybrf2bne24cjdbt4sjq