Systems supplying sediment to canyon heads (SSSCHs) in the Tyrrhenian Sea: The past and the present as a key to understanding deep-sea stratigraphy

摘要

Systems Supplying Sediment to Canyon or Slope Channel Heads (SSSCHs) initiate sediment transfer from the shallow water areas to the deep sea. SSSCHs are very sensitive to sea-level variations, to perturbations in sediment production and redistribution and to variations in accommodation in the shelf. Through the analysis of bathymetric and subbottom data, I review the variability in time and space of SSSCHs in the eastern Sardinian and northeastern Sicilian margins of the Tyrrhenian Sea. I distinguish three main types of SSSCHs: type I corresponds to shelf-edge deep-water coastal systems; type II corresponds to continental shelf, shoal-water coastal systems; type III is coast-disconnected. Further subdivisions involve the degree of confinement and the process-regime at the shelf-edge for Type I SSSCHs, and the distance from the canyon head and the process-regime for type II SSSCHs. Coast-disconnected type III SSSCHs consist of shelf-wide depositional belts, both un-channalised and channalised, as well as of landslide complexes.