Las secuencias oblicuas en el borde Norte de la Depresión del Ebro en Navarra y la Discordancia de Barbarín


  • Oriol Riba i Arderiu


Stratigraphic study is made on a long strip (>20 km) of steep verticalized continental Tertiary deposits located in the northern margin of the Ebro Basin (Navarra, Spain). The formations that bound up this unit attain an integrated thickness of 6860 m. This study focuses also on the regional Late Oligocene Barbarín angular unconformity and its continuation to Codés area, that has been recently questioned. This unconformity is related with one of the pyrenean folding phases, with the Estella diapir and with a set of NNE to SSW sinistral strike-slip faults. Depositional sequences (or UTS) are also studied. Due to displacement of sedimentary depocenters into the Ebro Basin, the boundaries of depositional sequences are oblique to isochrones («oblique sequencew). Also, within each sequence, one level of sedimentary vertical inversion may be identified located at the level where a change takes place from fining upwards to coarsening upwards sequences, which also migrate obliquely. For this reason they cannot be taken as indicators of isochronism.