3D geometry, structure and formation of the Duero basin within the Pyrenean Orogen geodynamic scenario

espanolLa Cuenca Cenozoica del Duero es una cuenca de antepais que presenta una geometria de gran sinclinal formado por la flexion litosferica y la subduccion de la corteza Iberica bajo la corteza Cantabrico-Europea. La estructura interna de la cuenca esta representada por fallas de alto angulo que involucran a basamento y cobertera, sin haber generado grandes desplazamientos horizontales. El frente orogenico septentrional esta representado por una serie de fallas dirigidas al sur que se enraizarian en la corteza inferior-media. Las relaciones tectonica-sedimentacion muestran que las fallas del interior de la cuenca fueron activas durante el Cretacico superior-Paleoceno, previamente a la etapa de antepais, mientras que el levantamiento del Orogeno y la actividad del frente de deformacion se produjo durante el Eoceno-Oligoceno, localmente hasta el Mioceno. La Cuenca del Duero se comporto como un contrafuerte de escala orogenica al carecer de una arquitectura extensiva previa heredada del rifting Jurasico Superior-Cretacico Inferior asociado a la apertura del Golfo de Vizcaya. La contraccion Alpina se focalizo alli donde la extension Mesozoica fue mas importante, como en el Margen Nor-Iberico y el sistema de cuencas extensivas Mesozoicas del rift Pirenaico. EnglishThe Duero foreland basin is characterized by a large synformal geometry formed by the lithospheric flexure and northward subduction of the Iberian crust underneath the Cantabrian-European crust. Basin structure is represented by high-angle faults that involve both basement and cover units, and that did not generate large amounts of horizontal displacement. The northern deformation front is represented by a series of S-directed faults that probably sole into middle-lower crustal levels. Growth strata within the basin interior indicate that basement faulting occurred during the uppermost Cretaceous to Paleocene, previous to the onset of the foreland stage, while the Orogen uplift and the northern deformation front activity took place mainly between the Eocene-Oligocene, locally protracting until Miocene times. The Duero Basin behaved as an orogenic scale buttress due to the lack of an inherited Late Jurassic-Early Cretaceous extensional architecture associated with the opening of the Bay of Biscay. Hence, most of the Alpine contraction had a major impact where Mesozoic extension was more important, like the North Iberian Margin and the system of Mesozoic extensional basins of the Pyrenean rift.