Resumen de Fosas neógenas asociadas a reactivación de pliegues en el borde sur de la Sierra de Cantabria (Alava-Navarra).
Ángel Luis Cortés Gracia, Antonio María Casas Sáinz
In the hanging wall oft he Sierra de Cantabria thrust (western sector of the southern Pyrenees) there are two Neogehe graben with long axes oriented NE-SW and E-W. They are 70x3 and 75x3 km wide, respectively, and filled with Miocene and Pliocene clastic deposits. Their southern margins are controlled by near vertical faults, which are roughly parallel to the strike of the Oligocene and Cretaceous beds, folded during the Pyrenean Tertiary shortening. These faults, formerly interpreted as normal extensional faults, can be explairied as the result of reactivation, during the Late Miocene to the Pliocene, of former flexural slip NE-SW and E-W compressional folds linked to thrusting. Structures formed on the uncomformable Neogene cover duririg this reactivation were conditioned by the thickness and lithological changes between Cretaceous and Oligocene units. The interpretation given to these Neogene graben implies that compressional structures extend at least to the Pliocene in this part of the southern Pyrenean border.
