Bedforms in the Southern Submarine Canyons of the Balearic Islands (Western Mediterranean) Interpreted as Cyclic Steps

Abstract

Multibeam bathymetric data collected along the Menorca Channel (Balearic Islands) for a depth range of 70–850 m revealed the occurrence of bedforms along some of the submarine canyons of the Balearic southern slope. The four main canyons presented in this study display a linear to sinuous geometry, incising the slope for up to 170 m and carving the shelf-edge at a depth of 110 m. Bedforms along these canyons are more developed along the two northernmost canyons, particularly within the 300–700 m depth range. The crescentic shape of the bedforms and their wavelengths of between 120 and 210 m resemble the morphology of bedforms found in other submarine channels and canyons. In line with these previously observed bedforms, we here explore the possibility that the bedforms in the canyons could be interpreted as cyclic steps formed by supercritical turbidity currents. Assuming this interpretation holds, then some simple modelling would allow us to give rough estimates of velocity and thickness of the flows that formed the cyclic steps.