Post-Jurassic tectono-sedimentary evolution of the Northern Lusitanian Basin (Western Iberian margin)

Seismic reflection and well stratigraphic data are used to investigate the post-Jurassic evolution of the Northern Lusitanian Basin, offshore west Iberia. Stratigraphic correlations between 11 exploration wells were attained in order to characterize the variations in depositional facies associated with salt tectonics. Latest Triassic-Hettangian salt, which generated multiple salt pillows during the Jurassic rifting, was reactivated after the early Aptian in two main phases. The first phase stretches from the late Turoman to the Maastrichtian. The second relates to Miocene tectonic inversion. The compression of the post-salt overburden caused the amplification of Jurassic detachment folds, forming barriers to the westward progradation of sediment into distinct salt-withdrawal sub-basins. Particularly during the Miocene, thin-skinned overburden shortening was accommodated by growing salt structures that suffered thrusting and extrusion. This structural style contrasts with that of salt-scarce areas where a simple westerly tilted, fault-bounded monocline was generated.