Acknowledgements
Aral I. Okay and Adrian F. Park provided constructive reviews of the paper. Curzio Malinverno provided the thin sections and Andrea Risplendente technical assistance at the microprobe. We acknowledge the support of PRIN 2008 “Tectonic trajectories of subducted lithosphere in the Alpine collisional orogen from structure, metamorphism and lithostratigraphy”. D.Z. acknowledges funding from the project: “Deformazione e metamorfismo delle ofioliti di alta pressione nelle Alpi Occidentali”, Università di Pavia.