The objectives of the Bankable cruise is to better understand the present-day dynamics and long term evoution of deep marine sand dunes and banks of the Iroise Sea located offshoree Brittany. The area corresponds to the junction area between the English Channel and the North Atlantic Ocean, well known for having strong tidal  currents and large swells. Indeed, the singular morpho-bathymetry of this segment of Brittany's continental shelf consists of a series of coastal reefs and islands catalysing and amplifying marine and hydrodynamics. Four main areas are examined : The Banc du Four, The Haut-Fond d'Ouessant, The Banc des Pierres Noires, The Banc d'Ar Men.

The approach is a comined survey including : multibeam bathymetry, High Resolution seismic sparker, side scan sonar, grab sedimentary sampling.

The objectives are to characterize:

• The sediment budget of the areas and the possible sand transfer betwwen the sand storage areas across the continental shelf.
• The horizontal migration velocities by comparison of previous bathymetry survey. The results will allow to  discuss the relative influence of forcings and the validity of the equations predicting bedform geometry in shallow waters.
• The Architecture of sand banks and the age of sand bodies to better understand the long term evolution of sand bodies in relation with the last transgression. It will allow to better examine  the relative influences of intrinsic sedimentary parameters and hydro-sedimentary processes, as well as post-glacial transgression and shelf paleomorphology in regards to tidal sand ridge growth.