Multiple-scale seafloor geomorphology in the southern Santos Basin, off Brazil: Interaction between salt tectonics and bottom currents

Continental margins shaped by salt tectonics typically undergo rapid burial by excess terrigenous sediment, which obscures the morphological record of interactions between endogenous and exogenous processes. Sediment-starved shelves preserve this record, enabling its study as the interactions shape abundant seafloor morphological features. This study integrates bathymetric, seismic reflection, and oceanographic data from the southern Santos Basin (SW Atlantic, 200–2000 m isobaths) to establish a scale-dependent framework for understanding how salt tectonics, fluid seepage, bottom currents, and gravitational processes interact. A tripartite scale-dependent classification shows systematic process dominance. At large scales, subsurface salt tectonics controls overall morphology, including the development of pockmark fields and canyon systems. At the same time, water-mass interfaces drive vertical zonation and the formation of marine terraces. At intermediate scales, interactions between salt-related structures, bottom currents, and gravitational flows govern the distribution and morphology of seepage-related features, including pockmark strings and small contourite moats along the flanks of aligned positive features. At smaller scales, localized hydrodynamic processes further modify individual features through erosion and sediment redistribution, reshaping primary structural controls.