Evidence for deep subduction of Austroalpine crust (Texel Complex, NE Italy)

We report here the discovery of UHP eclogites in the Ulfas Valley within the Texel Complex (Meran, NE Italy), which has important implications on the evolution of the Austroalpine nappe stack in the Eastern Alps. Exsolved K-feldspar and phengite lamellae within omphacite relics, together with an unusually high K-content of the host clinopyroxene, point to equilibrium pressures at least close to the quartz/coesite transition. The age of the high-pressure metamorphism is constrained by U–Pb dating of metamorphic zircon at 85 ± 4 Ma. These new data suggest pressure conditions for the Cretaceous eclogitic metamorphism of the Texel Complex higher than hitherto reported data, possibly indicating that several sectors of the Africa-Adria derived Austroalpine margin were subducted to mantle depths during the early stages of the Alpine orogeny.