Seafloor geomorphology of the Passage of Lanzarote (West Africa Margin): Influences of the oceanographic processes

Abstract

The seafloor morphology of the Passage of Lanzarote has been analysed with the aim to know the active processes on the bottom surface related to the oceanographic context. Multibeam bathymetric data and high and very high resolution seismic profiles obtained in the SUBVENT2 cruise have been used. Five main morphological groups have been analysed: (a) Volcanic or diapiric submarine hills; (b) Tectonic features on the continental slope (linear scarps and a rhombohedral depression) related to normal faults; (c) Submarine venting at top of diapirs initially triggered circular depressions; (d) Sedimentary instabilities (gullies, canyons, mass transport deposits) are present specially on the Fuerteventura-Lanzarote ridge; and (e) Contouritic bottom features both erosive (central valley, marginal valleys) and depositional (plastered drifts) are on the central part of the passage, and are generated by the interaction of MW and the interface MW-AAIW with seafloor.