Alpine deformation in the southern Cantabrian Front (Basque-Cantabrian Pyrenees, Spain): Kinematics and role of the Mesozoic structures of the BasqueCantabrian Basin southern margin

espanolThe Basque-Cantabrian Basin is an extensional Mesozoic basin which was inverted during the Alpine orogeny and incorporated to the Pyrenean contractive building. The outcrops located in its southern margin show both extensional Mesozoic and compressive Alpine structures, with the latter being commonly developed as a result of the inversion of the former. The Upper Triassic evaporites (Keuper facies) favoured the development of salt tectonics during the Mesozoic extension. Later, during the Alpine orogeny, they played an important role as a main detachment level. We present a detailed geological map and two geological cross-sections based on field data, which contribute to the understanding of the structural evolution of the southern margin of the Basque-Cantabrian Basin, focusing on the importance of Mesozoic structures and salt tectonics movements during the Pyrenean deformation. EnglishLa Cuenca Vasco-Cantabrica es una cuenca mesozoica que fue invertida e involucrada totalmente al edificio pirenaico durante la orogenia alpina. Su margen meridional posee un especial interes geologico ya que permite el estudio tanto de las estructuras extensivas mesozoicas como el de las compresivas alpinas desarrolladas, en muchos casos, a partir de la inversion de las primeras. La presencia de evaporitas del Triasico Superior (facies Keuper), favorecio durante la extension mesozoica el desarrollo de tectonica salina en la cuenca, mientras que durante la orogenia alpina actuaron como un nivel de despegue preferente. A partir de datos de campo y de subsuelo, se presenta una cartografia de detalle y dos cortes geologicos del margen sur de la Cuenca Vasco-Cantabrica que permiten comprender la evolucion estructural de este margen poniendo especial interes en el papel que tuvo tanto la estructura mesozoica como la tectonica salina durante la orogenia alpina.