Bathy-morphological analysis of submarine canyons across the north-western Sicily continental slope

Abstract

We present here the results of the morpho-bathymetric analyses of the main submarine canyons along the upper slope off the north-western Sicily. This region developed during the Neogene as the transition area between the Sicilian fold and thrust belt and the Tyrrhenian basin realm. Along the upper slope, a dense network of submarine canyon develops from 80 m water depth up to more than 2000 m, showing a large variability of sizes and morphology. In this area submarine canyons play a crucial role related to the along-slope sedimentary transport and are among the most distinctive features of the submarine seascape. This study is based on a quantitative analysis of a high resolution multibeam data set of the north-western Sicily offshore integrated with the topographic DEM of the adjacent continental region. Very different canyon-related morphological features along the study area mainly suggest the occurrence of top-down gravitational processes along canyons likely originated through a bottom-up evolution. By means of high resolution bathymetric data, we: i) described the main morphological features of submarine canyons; ii) measured the main morphometric parameters along canyon longitudinal profiles; iii) calculated the extension of different lithology outcropping on the river catchment areas corresponding to distinct river-fed canyons. For each analyzed canyon a chart was built in which bathymetric longitudinal profile, catchment area extension and gradient longitudinal profile have been reported. Quantitative analyses of longitudinal profiles reveal that the morpho-sedimentary evolution of mapped canyons is comparable to the corresponding fluvial environment, although presenting some differences. Integrated analysis of offshore data and river catchment areas suggest that the continental slope structural setting as well as the outcropping lithologies could be relevant control factors on the morpho-sedimentary evolution of the NW Sicilian canyons.