Integrated Geological Study in an Offshore Renewable Energy Test Site: An Example From the Basque Contiental Shelf (Bay of Biscay, Spain)

Abstract Testing and research centres for offshore renewable energy, exemplified by facilities like BIMEP on the Basque coast of Spain, play a crucial role in driving the energy transition. In this study, we utilize standardized data for this infrastructure, such as high resolution bathymetry or sediment samples, to conduct a comprehensive geological analysis including both sedimentary and rocky seabed. Our approach could serve as a methodological example that offers a cost-effective means to characterize offshore energy sites. We present a geological map that extends the main lithological formations from onshore to the continental shelf and identifies the main structures, including NW-trending folds and fractures predominantly oriented NE-SW. Sedimentary bottoms are analysed through a Seabed sediment map, illustrating a NE-SW oriented banded distribution attending to granulometry. Bedforms are also studied, they are asymmetric and mainly oriented NE-SW. The Seabed sediment map and the bedform analysis reveal the effect of a SE-directed bottom current as the main mechanism controlling sediment mobility. This current matches with the predominant swell from the NW and with the most energetic waves in the area.