Resumen de Sedimentary evolution of the eastern Bay of Biscay since the Upper Eocene

J. Iglesias Moscoso, Gemma Ercilla Zárraga, Soledad García Gil, Juan Tomás Vázquez, Francisco Javier Álvarez Pulgar, Gabriela Fernández Viejo, Jorge Gallastegui Suárez

• Analysis of sedimentary evolution from upper Eocene to Quaternary in the easternmost Cantabrian continental margin has been carried out by seismic profiles recovered during the MARCONI cruise. The stratigraphic division has been established based on the correlation with published seismic data. Six seismic units (1 to 6, from older to younger) and four main seismic sequences have been defined. The integration of seismic facies, stratal architecture and geological history analysis has allowed the reconstruction of its evolution. During Upper Eocene a syn-tectonic deposition of gravitative sediments and small turbidite fans occur. This scenario maintains during the Lower Oligocene until the interplay between the consecutive Mid Oligocene sea level falls and denudation of the emerging Cantabrian Mountains provokes an increase in sediment transference towards deep basin with formation of a thick stacking of slope aprons and sandy turbidity systems. During the Miocene predominates hemipelagic settling and the formation of proximal, small and starved turbidite systems in continental rise. Towards Upper Miocene a new period of high sediment transfer occurs that ended in the recent development of the large turbidite system created by the confluence of CapFerret, Santander and Torrelavega systems.