Fig. 11

Summary of metamorphic conditions and ages: Prealpine granulite facies metamorphism at 295 Ma (red point). Alpine subduction related high-P low-T metamorphism: Garnet in TGU at 57 Ma: Peak P–T conditions reached by the TGU (green symbols) and the ZSU (orange symbols) in the Zermatt area (average from Bucher et al. 2005; Angiboust et al. 2009; Bucher and Grapes 2009; age from Rubatto et al. 1998). Possible prograde paths for alpine subduction metamorphism and subsequent exhumation is constrained by the presence of stable Ol + Atg in the ZSU serpentinites (Li et al. 2004a). Exhumation of TGU and ZSU terminated at greenschist facies conditions (green circle). The conditions calculated for the matrix recrystallization of the TGU were reached along a prograde path (blue symbols) starting at the exhumation path and attaining the P–T maximum for this event not later than 34 Ma ago (Amato et al. 1999). The final exhumation path of both units is not shown