Tectonic evolution, geomorphology and influence of bottom currents along a large submarine canyon system: The São Vicente Canyon (SW Iberian margin)

A multi-scale dataset consisting of multi-beam echo-sounder, 2D multi-channel seismic and sidescan sonar (TOBI) data allows us to identify a large variety of morphologies originating from sedimentary and tectonic processes along the São Vicente Canyon (SVC), which is the largest submarine canyon developed in the external part of the Gulf of Cadiz. The SVC is located in one of the most seismogenic areas of Western Europe. The convergence between the Eurasian and African plates has controlled the formation and evolution of the canyon. The SVC is tectonically controlled by three main thrust faults: the Marquês de Pombal Fault, the São Vicente Fault and the Horseshoe Fault. No major rivers feed sediment to the canyon head, but the main sediment source is related to the dismantling of canyon flanks and the MOW (Mediterranean Overflow Water). This current contributes sediments by two different processes: a) conturites deposition at the head and flanks of the SVC that periodically fail into the canyon; and b) the coarser-grained and denser sediment of the MOW might be trapped at the head of the canyon and could develops into hyperpycnal flows. The SVC is characterized by retrogressive erosion being submarine landslide deposits and scars the main seafloor morphologies. The tectonic and stratigraphic interpretation of seismic profiles indicate that the SVC is a clear example of a diachronous and segmented canyon developed since the Late Miocene in an area of present-day active plate tectonics. This study investigates the interaction between active tectonics, the dynamics of submarine canyons and the resulting geomorphologies.