Estudi estratigràfic i estructural de la zona del Serrat-Arcalis

(ENG) The study area this year is located in the northwest of Andorra, from Arcalis to the Rialb Valley. This area is in the transitional zone between Pallaresa Dome and Aston and l'Ospitalet massifs.The field work allowed us to differentiate Cambro-ordovician, Upper Ordovician and Silurian materials. It was the first time that these last two materials were recognized in this area. Furthermore, the geological cross and the petrografical study show us three deformational events. These events are characterized by three different foliations. The first foliation (S1) is observed by microscope but not on the ground. The second foliation (S2) is the main foliation and is associated with north-verging folds. The third foliation (S3) is associated with upright folds with NE-SO to E-O trend. The metamorphism in this area is simultaneous with deformation development.