TETHYAN HERITAGE AND ALPINE POLYPHASE TEC TONICS - REINTERPRETATION OF THE AIGUILLE-DE-MORGES AREA (PELVOUX MASSIF, WESTERN ALPS)

The Aiguille de Merges area, south of the Pelvoux massif (External Cry stalline Massif, Western Alps), consists of thrust slices, involving b asement and Mesozoic cover rocks. A combination of Alpine strike-slip and thrust movements along a network of partially inherited Hercynian and Tethyan faults have be to envisaged. Two deformation episodes were found: a first NE-SW shortening, followed by an E-W shortening of pro bably Oligocene age. The Aiguille de Merges area was structured especi ally by the first one, along inherited faults which become sub-vertica l at depth.