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International audience; Thirteen seismic reflection profiles and field observations have been used to build a three-dimensional watertight geological model of the sub-surface architecture of the Trapanese carbonate platform unit of the Apennine-Maghrebian chain in the Mt. Kumeta and Mt. Rocca Busambra (NW Sicily, Italy). Either a single step or a two-step thrust-fault deformation model is acceptable on the basis of seismic interpretation but the integration of 3D model reconstruction and 3D geomechanical restoration, validates only the scenario with a single stage of deformation.The 3D model highlights along strike variations of the structural style for the Trapanese unit where pre-existing discontinuities (e.g. inherited Mesozoic normal faults) played an important role in the preferential occurrence of hinterland verging structures. In detail, backthrusts (N-verging) are dissected by tear faults along the Mt. Kumeta structure whereas an imbricate backthrust system evolves into thrust along the Mt. Rocca Busambra structure. Shortening estimate indicates low amount of internal deformation affecting the carbonate platform unit (

This study presents a global overview of the submerged speleothems used to reconstruct paleo sea levels and reports new results from two stalactites collected in the Mediterranean Sea. Coastal cave deposits significantly contributed to the understanding of global and regional sea-level variations during the Middle and Late Quaternary. The studied speleothems cover the last 1.4 Myr and focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. The results indicate that submerged speleothems represent extraordinary archives that can provide detailed information on former sea-level changes. The two stalactites collected in the central Mediterranean Sea, at Favignana and Ustica islands (Sicily, Italy), are both characterized by continental, phreatic or marine layers. The U-Th and 14C ages of the new speleothems provide results of great interest for relative sea-level changes over the last 1000 years.

The paleomagnetic investigation of the western Sicily Maghrebian belt has revealed since the 1970s that large clockwise rotations up to 140° with respect to the Hyblean-African foreland occurred synchronous with Tertiary shortening of the chain. The observation that rotations decrease stepwise from internal to external tectono-stratigraphic units led in the 1990s to a widely accepted model postulating that rotational thrust-sheet emplaced during forward orogenic propagation. More recently, other authors suggested that clockwise rotations from Sicily are conversely the result of late orogenic dextral strike-slip tectonics. Here we report on a paleomagnetic investigation of 30 Jurassic-Eocene sedimentary sites sampled mainly across the WNW-ESE Mt. Kumeta and Rocca Busambra ridges (Trapanese Unit), both bounded to the north by high-angle reverse faults with dextral strike-slip components. We find rotations of 110°–120° at faults of northern ridge margins, which decrease to 80°–90° at ~200m to the south and rise again moving further south. Thus, an excess rotation of 20°–40° due to dextral-strike-slip shear is annulled to the regional rotational background of the Trapanese Unit at only 200m from fault traces, translating to paleomagnetically calculated strike-slip offsets not exceeding 600m. Further north, seven sites sampled in the Imerese Unit, tectonically stacked above the Trapanese Unit, yield a ~130° rotation. Thus, our data confirm that CW rotations in Sicily are predominantly related to thrust-sheet emplacement. Strike-slip tectonics has very limited relevance and gives local rotations that fade out at only 200m from fault planes.

In this paper we present and discuss data concerning the morphostructural evolution at Ustica Island (Tyrrhenian Sea, Italy) during Late Quaternary. New insights on the relative sea-level changes of Ustica are coming from data collected during a geomorphological field survey around the island, together with the bathymetric analysis of the surrounding seabed and 14C datings on samples of speleothems, flowstones and marine shells found inside three selected sea caves. The survey was mainly accomplished on June 2015 through the first complete snorkel investigation off the about 18 km-long volcanic coast of the island, which allowed to precisely define location, relationship and morphometric features of coastal landforms associated with modern sea level. This study highlights the occurrence, for the first time in the Mediterranean, of tidal notches in correspondence of carbonate inclusions in volcanic rocks. The elevation of the modern tidal notch suggests that no significant vertical deformations occurred in the southeastern and eastern sectors of Ustica in the last 100 years. However, the presence of pillow lavas along the coast demonstrates that Ustica was affected by a regional uplift since the Late Quaternary, as also confirmed by MIS5.5 deposits located at about 30 m a.s.l., which suggests an average uplift rate of 0.23 mm/y. Radiocarbon dating of fossil barnacles collected inside the Grotta Segreta cave indicate an age of 1823 ± 104 cal. BP. The difference in height with respect to living barnacles in the same site suggests that their present elevation could be related to stick-slip coseismic deformations caused by the four earthquake sequences (two of which with Mw = 4.63 ± 0.46) that strongly struck the island between 1906 and 1924. © 2017 Elsevier B.V.