Slow and fast deformation in the Dora Maira Massif, Italian Alps: Pseudotachylytes and inferences on exhumation history

The Dora Maira Massif (DM), Western Alps is a type example of an ultra-high pressure (UHP) metamorphic terrain. The occurrence of pseudotachylytes within the Val Gilba area of DM led to speculation regarding the role of seismic slip in the exhumation of the massif. In this study, new field, microstructural and geochemical data on the pseudotachylyte veins and their mylonitic gneiss host are presented. The formation of pseudotachylyte veins occurred late in the exhumation history at 20.1 ± 0.5 Ma and at shallow depths (