SOREZOIS - A KEY POINT FOR AN UNDERSTANDI NG OF RELATIONS BETWEEN THEAXIAL ZONE AND THE VARISCAN NAPPES OF MONTAGNE-NOIRE (FRANCE)

In the western part of Montagne Noire, the Sorezois appears to be made up of four superposed units separated by major thrust planes: the Axi al Zone at the bottom, two para-autochthonous units pulled from the Ax ial zone and an uppermost to allochthonous unit which belongs the larg e Occitan domain together with the southern slope nappes and with the Monts de Lacaune. The Sorezois provides thus a model for the emplaceme nt of that domain: thrusting post-dates the synmetamorphic polyphase s tructuration but it is anterior to later phases of folding which induc e basin and dome structures, to wrench faulting and to extensional tec tonics.