Altérites et bauxites, témoins des marges européenne et ibérique des Pyrénées occidentales au Jurassique supérieur — Crétacé inférieur, à l'ouest de la vallée d'Ossau (Pyrénées-Atlantiques, France)

Abstract

Alterites and bauxites from Atlantic Pyrenees cropping out immediately west of the Ossau Valley (‘North-Pyrenean Zone’ in the literature) give information, by means of their ages within the Upper Jurassic-Aptian interval and of their depositional conditions (allochthonous or autochthonous) on the successive steps of the Iberian and European margins, about the extensional motions linked to the Lower Cretaceous rifting (opening of the Axial Basin). Pyrenean data are also interpreted in a larger Tethyan context where principal factors are the changes of climate, atmospheric CO 2-O 2 ratio and sea level.