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MORPHOLOGY AND RECENT SEDIMENTARY EVOLUTION OF THE WESTERN
SICILIAN CONTINENTAL SHELF

Paolo Colantoni*, Marco Ligi**, Maria Paola Morsiani*** & Daniela Penitenti**

* Istituto di Geodinamica e Sedimentologia, Università di Urbino, Italy
** Istituto di Geologia Marina CNR, Bologna, Italy
*** Via F. Cilea 85 - Sassuolo, Italy

Abstract
The main bathymetric and morphological features of the continental shelf off western Sicily are
described. A deeply eroded substratum of older and tectonized rocks is covered by a thin carpet of
sediments of biological origin. Sediment accumulates only in subsiding Plio-Quaternary basins while on
the shelf erosion and transport prevail.

Introduction the shelf arounf Marettimo Island and the wide
Modern views on sedimentary sequences Adventure Bank that extends as far south as
recognize that a relationship exists between Pantelleria Island (Fig. 1). From a structural
relative sea-level changes and broad depositional point of view, the entire area belongs to the
patterns, especially on continental shelves. In deformed African foreland. Here, seismic
particular, eustatic changes and subsidence profiles and drilling have identified a Neogene
combine to produce space for sediment deposition fold and thrust belt chain, composed of different
and conservation. In shelf areas characterized by tectonic units, that joins Tunisia to Siciliy.
uplift or stability, eustatic fall usually results in In particular, in the Egadi sector of the
erosion of sediments associated with the previous Magrebian-Sicilian belt, thrust sheets derived
eustatic rise. from the Tortonian deformation of the Pre-
The area off-shore Trapani, Marsala and Panormide paleogeographic domain have been
Mazzara del Vallo (west and southwest of Sicily), thrust southward over deformed units of the
that comprises the Egadi Islands and the Adventure Trapanese domain. South-eastward, deformed
Bank, can be regarded as a good example of a shelf Tortonian terrains onlap imbricate units of the
affected by marine abrasion of a rocky, tectonized Adeventure Bank, that during the Miocene acted
substratum, where scarce recent sediment deposits as structural foreland (Catalano and D?Argenio,
are mainly composed of bioclastic fragments. 1990).
The aim of this paper is to present the The direction of the thrust fronts is mainly
principal bathymetric, morphological and from the NNE toward the SSW but from
sedimentological aspects of this important area, Messinian times, tensional stresses cut the area
which is located in a complex geological setting with NNW-SSE and E-W faults. Deep basins
and is swept by strong currents linked to the water were originated during this extensional phase
exchanges between the western and eastern basins and were associated with volcanic activity. A
of the Mediterranean Sea. The data (bathymetric Plio-Pleistocene tectonic inversion (Argnani,
and seismic profiles and samples were collected 1990) subsequently reactivated some lineations
during several oceanographic cruises carried out and originated strike-slip faulting.
by the Istituto per la Geologia Marina of Bologna. The main paleo-geographic domains are
Notes on the Adevnture Bank have been published shown by depositional sequences that begin with
previously by Colantoni et al. (1985). carbonate platform limestones of Triassic-Early
Jurassic age. These shelves are overlain by
Geographical and geological setting
Jurassic-Early Miocene pelagic limestones
The area is located on the continental shelf (scaglia), clastic (sandstones and sandy marls).
off the western Sicily between Capo S. Vito and From Tortonian to Pleistocene evaporites and
Capo Granitola, and ranges between 36°45’ N and terrigenous deposits accumulated in pre-
38°12’ N and between 11°30’ E and 12°45’ E. Messinian and Pliocene deformed basins,
Three geographic units can be recognized channels and banks where rocks of different
that are referred to the Sicilian continental shelf, ages may outcrop.
that comprises Favignana and Levanzo islands,

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