Dr Andrea Boscaini - Nothing lasts forever: Post-collisional magmatism and the collapse of the Variscan orogenic belt

The tectonic re-equilibration after the Variscan orogeny coincided with widespread early Permian post-collisional magmatism in southern Europe. The lack of high-precision geochronological data and the evolved and crustally-contaminated compositions of these magmatic rocks preclude a full understanding of the origin of such widespread post-collisional magmas, as well as their relationship to major tectonic events. Here, we present new high-precision zircon U-Pb geochronological data obtained by chemical abrasion isotope dilution thermal ionization mass spectrometry (CA-ID-TIMS) for the early Permian (ca. 280 Ma) Athesian Magmatic District (AMD) in NE Italy. Our new ages allowed us to refine the lifetime of the Athesian district. Moreover, combining these ages with recent high-precision ages from other South Variscan magmatic systems, we recontructed the spatial and temporal evolution of the early Perimian post-collisional magmatism in the southern Alps. Finally, geochemical and radiogenic isotopic modelling was applied to investigate the primary source of the South Variscan post-collisional magmatism and how this was related to the demise of the Variscan orogeny.