Les concentrations à sillimanite du Sud Velay et l'évolution P-T-t fini-hercynienne dans le Massif central (France)

The Late Hercynian evolution in the French Massif Central corresponds to the transition from a LP-HT (M3 event at 314 ± 5 Ma) to a higher temperature metamorphism corresponding to the emplacement of the Velay granite dome (M4 event at 301 ± 5 Ma). This transition is outlined by the development of sillimanite folia, which represent planes of base-cation leaching, associated with ductile deformation. This evolution implies a counterclockwise retrograde P-T-t path under subsolidus conditions between M3 and M4. To cite this article: P. Barbey et al., C. R. Geoscience 337 (2005).