Contemporaneous opening of the Alpine Tethys in the Eastern and Western Alps: constraints from a Late Jurassic gabbro intrusion age in the Glockner Nappe, Tauern Window, Austria

Abstract Metabasic rocks of the ophiolitic sequences Glockner Nappe and Eclogite Zone in south-central Tauern Window, Austria, reveal important insights into rifting spreading Alpine Tethys. U–Pb dating magmatic zircons yields a concordant 157 ± 2 Ma crystallization age for precursor coarse-grained metagabbro from Nappe. The Late Jurassic intrusion is coeval with mafic plutonic activity Western Central Alps. Although Penninic tectonic windows Eastern Alps are usually disrupted, an ocean–continent transition setting can be reconstructed Nappe, similar to many ophiolites Liguria–Piemont domain Together, these observations strongly suggest formation branch Tethys inconsistent Valais domain. This finding has implications paleogeographic reconstructions realm Whereas metabasalts clearly their depleted mantle origin, metabasic record more complex history involving melting crustal assimilation continental margin setting.