Sedimentary Settings on Continental Margins — an Overview

Sedimentation on continental margins bears the strong imprint of the tectonic setting, changes of sea-level and many local processes, including human intervention in sediment supply. Carbonate sediments are mainly created within the depositional basin whereas clastics supplied from upland areas are susceptible to enhancement due to deforestation or cut-off due to damming. Quaternary oscillation of sea-level has occurred with a frequency that has generally prevented supply and dispersal systems coming to equilibrium. Thus shelf shape reflects low-stand of sealevel and sediments dispersed from outer shelves/upper slopes were mainly emplaced at low stand — only in cases of maj or deltas has delivery overcome post-glacial sea-level rise. Dispersal processes of waves, tidal currents, wind-driven currents, oceanic currents and slope currents, and gravity flows down slopes and in canyons are briefly outlined. Major areas of uncertainty remain in budgets where flood-plain storage is generally unknown, the amount (and grain size distribution) trapped on shelves versus escaping to the ocean is unknown, and the magnitude/frequency structure of modern mass flows in canyons is poorly known.