| Abstract: | Field observations of the “Chaînons béarnais”, in the area of Oloron-Sainte-Marie, reveal two families of units: The first one contains a well developed Jurassic-Cretaceous series, it structurally underlies the second one. The second one contains a thin Jurassic-Cretaceous series, deposited on a basement including metamorphic Paleozoic terrain and lherzolites. The structural arrangement, as well as the sedimentological characteristics, suggests a southern origin for these highest units.The tectonic association between metamorphic and ultrabasic rocks of the basement was probably formed during the Hercynian orogeny, or in a Late Hercynian period. However, it clearly predates fossiliferous sediments attributed to the Callovo-Oxfordian (Pic de Saraillé, Lourdios) or still undated terrains presenting a typical Triassic facies (Tos de la Coustette, Lourdios). |
