Fig 1.
Physiographic map of the Sicilian Channel.
Bathymetry taken from EMODnet Digital Terrain Model (1/16*1/16 arc minutes), downloaded from http://www.emodnet-bathymetry.eu/. Contours every 200 m. Abbreviations: GB, Graham Bank; TB, Terrible Bank; NB, Nerita Bank; NaB, Nameless Bank. Black rectangles indicate the areas where high-resolution bathymetric data are available (see Fig 2A and 2B). The dotted thin black segments indicate the main traces of the Capo Granitola (CGF) and Sciacca (SF) faults (modified from [27]). The small blue stars indicate the points where the Relative Sea Level (RSL) curves for the Adventure Plateau have been calculated (see Fig 6).
Fig 2.
Multibeam data of the Mazara del Vallo-Sciacca marine sector (A), and of the eastern margin of the Adventure Plateau (B) where the analysis has been carried out (see boxes in Fig 1). Positions of the corresponding Chirp profiles presented in Fig 4 are indicated. (C) Representative bathymetric profiles for the two analyzed sectors (corresponding locations in Fig 1A and 1B). The profiles were taken perpendicular to the maximum gradient associated to the post-LGM sea level rise. Data show that the bathymetric trends in the water depth ranging from 90 to 140 m are very different between the two areas taken into consideration. See text for details.
Fig 3.
2-D simplified sketch of a low-gradient shelf.
Shoreline configuration at the LGM (upper panel) and at a generic time-frame following the LGM where the sea level has rose (lower panel). The thick red segment indicates the "wave-ravinement erosional surface" (WRS).
Fig 4.
High-resolution seismic profiles.
Representative Chirp profiles acquired off the SW coast of Sicily between Mazara del Vallo and Sciacca, and along the eastern margin of the Adventure Plateau (see Fig 2 for location). Red arrows indicate the locations of the post-LGM marine transgression. The depth vertical scale has been calculated applying a constant sea water sound velocity of 1512 m/s. See text for details.
Fig 5.
Equivalent Sea Level curves (ESL) for the GIA model during the last 30,000 years.
The total ESL is marked by ANU (Australian National University); NA, North America (with Greenland and Iceland); EUR, Fennoscandia (including Barents-Kara); ANT, Antarctica; ANH, Alpine Glaciers (Northern Hemisphere); ASH, Alpine Glaciers (Southern Hemisphere); BI, British Isles. The three major components are clearly NA, ANT and EUR.
Fig 6.
Relative Sea Level (RSL) for the Adventure Plateau.
RSL curves calculated for the following points in latitude-longitude: 37.4°N 12.6°E; 37.4°N 13.0°E; 37.4°N 12.7E°; 37.3°N 12.4°E; 37.2°N 12.9°E (see locations in Fig 1). Note that the variations in sea-level in the various points are so small that the curves are practically overlapping and indistinguishable each other. The dashed curve is the eustatic curve for model ANU (Australian National University). The five curves differ by ~15 m at the LGM (21 kyrs).
Fig 7.
Relative sea level variation since 21 kyrs B.P. for the entire Mediterranean Sea obtained with SELEN4.
The upper panel indicates the sea-level contours (in meters) at 21 kyrs B.P., the lower panel indicates the palaeo-topography at 21 kyrs B.P. (in meters).
Fig 8.
Evolution of the NW Sicilian Channel coastlines at different epochs.
Maps obtained from the GIA model for the NW sector of the Sicilian Channel, showing coastline configuration every 500 years. The small red dots indicate the geographical positions of the beginning of the post-LGM marine transgression, as individuated from the analysis of the high-resolution seismic data.
Fig 9.
Palaeo-coastlines in the sector comprised between Mazara del Vallo and Sciacca from 21 to 19.5 kyrs B.P.
In this sector, where the density of the available data is maximum, we have identified in detail the beginning of the post-LGM marine transgression (small red dots). The RSL curves for this sector have been also mapped (green lines).
Fig 10.
Distances between points derived from the GIA model and points derived from the interpretation of seismic data.
It is noted that at 21 kyrs B.P., the average differences between the points are minimal, which means that the beginning of the marine transgression took place from 21 kyrs B.P.