Over the past decades, the northern Gulf of Cadiz has been the focus of a wide range of late Quaternary seismic and sequence stratigraphic studies, either addressing the slope contourite depositional system (CDS), or the development of the continental shelf. Yet, high-resolution seismic data bridging between these domains and age information have remained sparse. This study, based on new high-resolution reflection seismic profiles calibrated to IODP Expedition 339 sites U1386/U1387, now presents an updated stratigraphic framework, that integrates (for the first time) the late Quaternary records of the northern Gulf of Cadiz middle slope to shelf off the Guadiana River. Seismic stratigraphic analysis of the stacking, depocenter distribution, stratal architecture and facies of the seismic (sub-)units reveals the influence of ~100 kyr sea-level variations paced by Milankovitch (eccentricity) cycles, tectonics (manifesting as two pulses of uplift and margin progradation), sediment supply and bottom current activity. This work furthermore contributes to the application and understanding of high-resolution, late Quaternary sequence stratigraphy. Firstly, the proposed sequence stratigraphic interpretation shows that adaptations to the basic models are required to integrate the shelf and slope record, and to account for the presence of a significant alongslope (bottom current-controlled) component. Secondly, the results confirm that the sequences are dominantly composed of regressive deposits, whereas the preservation of transgressive to highstand deposits is more irregular. Significantly, the common assumption that successive major glacial lowstands are consistently recorded as well-marked, shelf-wide erosional unconformities, is demonstrated to be occasionally invalid, as tectonics can obliterate this one-to-one relationship.

T. Mestdagh is supported by a doctoral scholarship of the Ghent University Special Research Fund (BOF), Belgium. This research was conducted in connection with ‘The Drifters Research Group’ of the Royal Holloway University of London (UK), and is related to projects funded by the Spanish government with project codes: CTM 2012-39599-C03, CGL2016-80445-R ‘SCORE’ (AEI/FEDER, UE), CTM2016-75129-C3-1-R, CGL2011-30302-C02-02 and CTM2017-88237-P. We wish to thank the captains, crews and scientific parties of research cruises COMIC 2013 on board of RV Belgica and LASEA 2013 on board of RV Ramón Margalef. Ship time on RV Belgica was provided by BELSPO - Belgian federal government (Belgium) and RBINS-OD Nature. Editor A. Negri, C. Pellegrini and one anonymous reviewer are kindly acknowledged for providing constructive reviews and feedback.