Submarine Canyon-Infill Evolution and Stratigraphic Response to Sediment Supply Variability During the Late Quaternary: the Blanes Canyon Head (NW Mediterranean)

This study investigates the stratigraphic architecture and evolution of the Blanes canyon head (NW Mediterranean) during the Late Quaternary using high-resolution bathymetry and seismic profiles (TOPAS and Sparker). The canyon forms a morpho-depositional boundary between the sediment-starved La Planassa shelf to the east and the depositional Barcelona shelf to the west. The Messinian Erosion Surface marks the base of the Pliocene succession and controls the accommodation and distribution of Quaternary deposits, which are directly emplaced onto the Miocene substrate due to the limited preservation of Pliocene sediments. Five Quaternary seismic units (A–E) infill the canyon head and are bounded by four unconformities (SB1–SB4) correlated with ∼100 kyr glacioeustatic cycles (MIS 10, 8, 6 and 2). The succession records marked asymmetry between canyon rims driven by inherited structural controls, asymmetric sediment supply and sea-level cyclicity. The western rim is predominantly depositional, comprising stacked progradational, downstepping wedges (Units A–D) formed during forced regression and overlain by Unit E, which records the last lowstand and subsequent transgressive deposits preserving progradational configurations. In contrast, the eastern rim is largely erosional, reflecting the combined influence of limited sediment input, reduced accommodation associated with a structural high, and subaerial exposure during sea level lowstands.Although adjacent to the Tordera River, no direct fluvial connection with the canyon head developed during the Late Quaternary. During lowstands, fluvial sediments were trapped within an inherited structural paleodepression along the western rim, accumulating as regressive infill rather than bypassing to the canyon. Four buried paleochannels record incision and canyon-head retreat during lowstands, followed by progressive infill. Overall, canyon-head evolution reflects structural inheritance modulated by Quaternary sea-level oscillations and sediment supply.