Morphosedimentary characterization of the Capbreton submarine canyon system, Bay of Biscay (Cantabrian Sea)

Abstract

Various studies have been carried out to the declaration of new marine protected areas for their importance for habitats, according to the Natura 2000 Network. One of these sites is a sector of the Capbreton Submarine Canyon System, located in front of the Basque Country coast, in the Bay of Biscay (North Atlantic). During the Intemares\_CapBreton 0619 and 0620 surveys; bathymetric, backscatter, high-resolution parametric data and samples of sediments, rocks and benthic communities from the seabed were acquired. The study was completed by recording video transects with the underwater vehicle ROTV Politolana from the IEO. The processing and analysis of the geophysical information has allowed obtaining a detailed bathymetry grid of 10 x 10 m, from which the first morphosedimentary characterization of the system of tributary canyons to the E-W trending main canyon and its interfluves has been made. One of the main features of this canyon system is the presence of a large pockmark field on adjacent platforms between canyons, located between 500 and 1000 m water depth. Within this field, pockmarks are shown as circular to elliptical depressions, most likely related to gas rich-fluid emissions to the subsurface.