The Andatza coarse-grained turbidite system (westernmost Pyrenees) : stratigraphy, sedimentology and structural control

espanolEn este trabajo se describe la estratigrafia y sedimentologia de la Formacion Conglomerados de Andatza. Mediante el analisis de facies se han interpretado tres asociaciones de facies principales correspondientes a un sistema turbiditico (de grano grueso) y al talud: un sistema turbiditico interno (o canon), un talud fangoso de alto gradiente y otro de bajo gradiente. La distribucion cartografica de las asociaciones de facies junto con el analisis de paleocorrientes describen un modelo sedimentario de sistema turbiditico de grano grueso en forma de “L” para los Conglomerados de Andatza, cuya morfologia fue controlada por fallas normales sinsedimentarias de basamento. El caracter grosero del tamano de grano de este sistema turbiditico indica la proximidad del area fuente de los conglomerados, que alimentaria el canon turbiditico desde el norte a traves de una estrecha plataforma marina. EnglishThis is a field-based work that describes the stratigraphy and sedimentology of the Andatza Conglomerate Formation. Based on facies analysis three facies associations of a coarse-grained turbidite system and the related slope have been identified: (1) an inner fan of a turbidite system (or canyon) and (2) a low- and (3) a high-gradient muddy slope respectively. The spatial distribution of the facies associations and the palaeocurrent analysis allow to interpret a depositional model for the Andatza Conglomerates consisting of an L-shaped, coarse-grained turbidite system, whose morphology was structurally controlled by synsedimentary basement-involved normal faults. The coarse-grained character of the turbidite system indicates the proximity of the source area, with the presence of a narrow shelf that fed the turbidite canyon from the north.