GEOLOGICAL HISTORY OF THE MORVAN
Namurian to Westphalian
Sudetic II Orogenic Phase
The Sudetic II orogenic phase is the main fold event undergone by Devono-dinantian series in the northeastern Massif Central. Intensity of fold deformation decreases from South to North, from Monts de Tarare up to Morvan region. In Montagne Bourbonnaise fold axes are E-W oriented and fold planes are S-SE overturned [REF].
Submeridian strikes of fold axes observed in the south Morvan belt, deviate along a NE direction in the region extending from Saint-Honoré-les-Bains to Lucenay-l'Evêque. In the normal folds shown by volcano-sedimentary beds, dips vary strongly from horizontal to sub-vertical. In regard of south Massif Central where Sudetic II Orogenic Phase is responsible of metamorphic tectonic nappes emplacements, the Devono-dinantian series remain gently folded and non-metamorphosed.