Salt tectonics in the Parentis Basin (Eastern Bay of Biscay)

Abstract

review of seismic data denotes that salt tectonics played an important role in the evolution of the Parentis Basin. Salt structures have been strongly influenced by the thickness of the Mesozoic sequence overlying the Triassic salts. They are widespread and show a more evolved development in the areas where the Jurassic-Lower Cretaceous successions are relatively thin. Thus in the eastern Parentis Basin, at the southern margin of the main half graben, salt ridges, salt walls, diapirs and glaciers occur. In the western part, where the Mesozoic succession is thicker, diapirs are less developed and restricted to the Landes Fault along the southern edge of the basin. On the contrary, salt ridges show a greater size. Salt structures were initially developed at Albian-late Cretaceous times after the syn-rift faults and contemporaneously with the opening of the Bay of Biscay. Subsequently they were rejuvenated during late Eocene-Middle Miocene as the Pyrenean deformation progressed into the northern foreland.