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                                                                Sea–land geology of Marettimo (Egadi Islands, central Mediterranean sea)

                                                                M. Gasparo Morticelli, A. Sulli and M. Agate

                                                                Dipartimento di Scienze della Terra e del Mare, Università degli studi di Palermo, Palermo, Italy

                                                                ABSTRACT                                                                                      ARTICLE HISTORY
                                                                                                                                                              Received 24 July 2015
                                                                We present a 1:10,000 scale geological map of Marettimo Island and its offshore (Egadi        Revised 1 December 2015
                                                                Archipelago, central Mediterranean Sea). The map was achieved by integrating a new            Accepted 1 December 2015
                                                                geological survey with data from recent, marine, geological and geophysical surveys
                                                                acquired along the adjacent continental shelf. The island is composed of a Mesozoic, mostly   KEYWORDS
                                                                carbonate platform succession, which is overlain by continental to coastal marine Quaternary  Geological survey;
                                                                deposits. Extensional tectonics have affected the carbonate platform since the Late Triassic  stratigraphy; tectonics; Egadi
                                                                producing an initial increase of accommodation space that was filled by interbed breccias,     Islands
                                                                marls and calcareous marls. During the Jurassic, a NE-SW-directed normal fault-bounded
Downloaded by [Universita di Palermo] at 02:49 07 January 2016  structural lows where thick beds of megabreccias accumulated followed upwards by cherty
                                                                limestone and bedded cherts. During the building of the chain, the compressional tectonics
                                                                generated a southeast-verging tectonic wedge, displaced by subsequent transpression.
                                                                During the Quaternary, repeated sea-level changes shaped a rough erosional surface along
                                                                the inner shelf and controlled the lateral facies variation of the continental and marine
                                                                coastal deposits along the present day coastline.

                                                                1. Introduction                                            Cartography) and GEBEC Sud (Agate, Catalano, Lo
                                                                                                                           Iacono, & Chemello, 2005) projects.
                                                                The stratigraphic and structural setting of the Maret-
                                                                timo Island (Italy) and its offshore are here illustrated     The topographic basemap is the Section 604010, per-
                                                                with a detailed geological map at a scale of 1:10,000,     taining to the Carta Tecnica Regionale, at a scale of
                                                                based on an integrated sea–land geological/geophysical     1:10,000 (vector file format .dwg, plane coordinates of
                                                                survey. Marettimo Island, belonging to the Egadi           the East Zone of the Gauss-Boaga Italian national system
                                                                Archipelago and located in the western Sicily offshore     geographical projection, datum Rome 1940, Monte
                                                                (central Mediterranean Sea, Figure 1(a)), represents       Mario). The bathymetric basemap is Sheet 260 of the Isti-
                                                                the westernmost outcrop of the Sicilian Fold and           tuto Idrografico della Marina, at a scale of 1:50,000. Both
                                                                Thrust Belt (FTB). A reliable understanding geological     contour lines and isobaths are at a 10-m interval. To
                                                                evolution of Marettimo Island, a natural bridge            improve the legibility of the geological map, the topo-
                                                                between the Sicilian and Tunisian sectors of the Apen-     graphic vector file was cleaned of some toponyms as
                                                                ninic–Maghrebian FTB (Figure 1; see also the top-left      well as cadastral and administrative boundaries.
                                                                regional map inset in the map), is a crucial contribution
                                                                to the regional geological framework of the central           The marine geological map results from the overlay
                                                                Mediterranean. We also present the submerged coastal       of different information layers:
                                                                zone (up to −50 m) to continue and correlate outcrop-
                                                                ping and submerged geological features. In doing this,     . distribution of sediments based on different texture;
                                                                we note the stratigraphic relationships between conti-     . outcrops of the late Quaternary depositional
                                                                nental and coastal marine sediments.
                                                                                                                              sequence and the underlying lithostratigraphic
                                                                                                                              units and
                                                                                                                           . outcropping and buried tectonic lineaments.

                                                                2. Data and methods                                        3. Geological background

                                                                The geological map of Marettimo is the result of a         The geological setting of the Egadi Islands, located in
                                                                recent, detailed field survey reproduced at a scale of      the western Sicily offshore (Figure 1) is due to the col-
                                                                1:10,000. The fieldwork included stratigraphic, sedi-       lision between the Sardinia-Corsica micro-plate and
                                                                mentary facies and meso-structural analyses. We inte-      the northern edge of the African continental margin,
                                                                grated the field data with results of previous marine       starting from the early Miocene (Bellon, Coulon, &
                                                                geological and geophysical surveys, performed in the       Edel, 1977; Channel, D’Argenio, & Horvath, 1979;
                                                                framework of the CARG (Italian official Geological          Dercourt et al., 1986). From the Egadi Islands to

                                                                CONTACT M. Gasparo Morticelli
                                                                © 2016 M. Gasparo Morticelli
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