Datación magnetostratigráfica de la molasa Surpirenaica (Fm Uncastillo, Oligoceno-Mioceno)

The Uncastillo Fm crops out along the southern boundary of the External Sierras, which represents the southernmost limit of the Pyrenean Range. Three tectosedimentary units related to tectonic pulses have been previously differentiated in this formation. The sedimentary evolution of the Uncastillo Fm is mainly related to the tightening of the WNW-ESE Santo Domingo anticline in the External Sierras during Chattian-Aquitanian times and records the younger tectonic movement of the south Pyrenean sole thrust. The Uncastillo Fm represents the change to overall southwardflowing alluvial and fluvial systems from overall west-northwest-flowing fluvial systems (Campodarbe Fm). Recent magnetostratigraphic results from the underlying Campodarbe Fm shift to younger ages (from chron 10r to 7r) the top of the Campodarbe Fm in the proximal area of the fluvial system (Luesia fan). In order to check that reassignment and refine the age of the Uncastillo Fm, a new magnetostratigraphic study has been conducted in laterally equivalent deposits that represent middle-distal areas located to the east of the Luesia fan. These deposits consist of mudstones with interbedded sandstones. These finer grain size sediments allow for a magnetostratigraphic sampling in the Fuencalderas section of ~1300 m, which complete the chronostratigraphic frame of the last tectonic pulses of the Pyrenean Range.Trabajo financiado por los proyectos SEROS (CGL 2014-55900-PL), DR3AM (CGL2015- CGL2014-55118) y Grupos Geotransfer y Análisis de Cuencas de la Universidad de Zaragoza. Es una contribución del Institut de Recerca Geomodels y del Grup de Geodinàmica i Anàlisi de Conques (2014SGR467).Peer Reviewe