Polyphase Permo-Carboniferous magmatism adjacent to the Intra-Sudetic Fault: constraints from U–Pb SHRIMP zircon study of felsic subvolcanic intrusions in the Intra-Sudetic Basin, SW Poland

Abstract The SHRIMP U–Pb dating of zircons from felsic subvolcanic rocks in the Carboniferous formations Intra-Sudetic Basin SW Poland verifies previous views on timing Late Palaeozoic magmatic activity this area and constrains links between regional tectonics intra-basinal volcanism mid-European Variscides. Two main stages magmatism are identified: late orogenic stage, Early Permian post-orogenic stage. to volcanic was contemporaneous with formation Karkonosze granite pluton west comprised episodic emplacement predominantly laccoliths sills within basin fill during Westphalian–Stephanian two sub-stages at ca. 313–310 Ma 306–305 Ma. Local folding succession peaked 303–300 adjacent Fault, relation late-stage sinistral movements along wrench fault. minor intrusions 293 completed northern Basin; volcanism, however, developed fully areas further south. predominance over extrusions can be linked trapping rising magmas several kilometres thick sedimentary fill. Zircon xenocrysts indicate that older crustal lithologies, possibly metamagmatic metasedimentary dominantly Neoproterozoic–Palaeozoic ages, were involved petrogenesis as magma sources and/or contaminants. influence stronger earlier events.