The Variscan subduction inheritance in the Southern Alps Sub-Continental Lithospheric Mantle: Clues from the Middle Triassic shoshonitic magmatism of the Dolomites (NE Italy)

Although often speculated, the link between Middle Triassic shoshonitic magmatism at NE margin of Adria plate and subduction-related metasomatism Southern Alps Sub-Continental Lithospheric Mantle (SCLM) has never been constrained. In this paper, a detailed geochemical petrological characterization lavas, dykes ultramafic cumulates belonging to magmatic event that shaped Dolomites (Southern Alps) was used model composition evolution underlying SCLM in time comprised Variscan subduction opening Alpine Tethys. Geochemical models numerical simulations enabled us define 5–7% partial melting an amphibole + phlogopite-bearing spinel lherzolite, similar Finero phlogopite peridotite, can account for primitive Mid-Triassic SiO2-saturated -undersaturated melts with affinity (87Sr/86Sri = 0.7032–0.7058; 143Nd/144Ndi 0.51219–0.51235; Mg # ~ 70; ~1.1 wt% H2O). By taking into H2O content documented mineral phases from it is suggested source able preserve significant enrichment volatile (600–800 ppm H2O) more than 50 Ma, i.e. since slab-related connected subduction. The Finero-like represents exhaustion signature lithosphere predated Late Triassic-Early Jurassic asthenospheric upwelling related