Geosciences Seminar Fri, 02/19/2016 - 13:26

"Post-Hercynian tectonic and paleogeographic evolution of the SW of Iberia and Gulf of Cadiz" by ADRIÀ RAMOS, Universitat de Barcelona (UB), will be held at room Sala d'Actes of Institut de Ciencies del Mar (ICM - www.icm.csic.es).

ABSTRACT:

The Algarve And Gulf of Cadiz basins are a Meso-Cenozoic sedimentary basin overlying Carboniferous basement, located in the southwestern margin of the Iberian Peninsula. Its structure reveals a protracted tectonic history comprising various pulses of Mesozoic extension followed by Cenozoic compression. This presentation deals with the structure along this margin, where the Mesozoic extensional structures and Cenozoic inversion structures are present, both offshore and onshore. The strike of the extensional structures ranges from E-W to N-S, as controlled by a shift from Tethyan-dominated extension in the east to Atlantic-dominated extension in the west. Contractional structures are inverted extensional structures, following their same trends. It is argued that the thickness of the Hettangian evaporite layer exerts a strong control on the structural style throughout the basin during the extensional and inversion episodes. The basin is affected by thick-skinned deformation along the northern margin, where salt is thin or absent, basement involved fault systems and short-cut structures. Basinward, as the Hettangian salt thickens, the margin is affected by thin-skinned deformation, with listric and down-to-the-basin growth faults, diapirism and salt-cored detachment folds. The SW of Iberia is currently undergoing compression related to the convergence between Iberia and Africa. Multiple contractional features have been documented both immediately west and east of the Gulf of Cadiz in recent years. Nevertheless, we document contractional structures that provide linkage across the Gulf of Cadiz and play a major role in defining the present-day bathymetry of this area.