Cinzia Albanese

Sicily’s fold–thrust belt and slab roll-back: the SI.RI.PRO. seismic crustal transect

Sicily is a thick orogenic wedge formed by (1) the foreland (African) and its Sicilian orogen and (2) the thick-skinned, Calabrian–Peloritani wedge. The crust under central Sicily, from the Tyrrhenian margin to the coastline of the Sicily Channel, has been investigated by the multidisciplinary (SI.RI.PRO.) research project. The project dealt with the nature and thickness of the crust and depth and geometry of the Moho, which is essential in formulating subduction models and improving the knowledge of African and Tyrrhenian–European lithospheres. The results resolve features such as (1) the main orogenic wedge, (2) the very steep, NW–SE-trending regional monocline suggesting inflection of the foreland crust, (3) the deep Caltanissetta synform imaged, for the first time, to about 25 km, and (4) the top of the crystalline basement and the inferred crust–mantle boundary. The SI.RI.PRO. transect confirmed that the NNW-dipping, autochthonous Iblean platform of SE Sicily and its basement extends all the way into central Sicily. Further NW, towards the NNW end of the transect, a large uplift involves the Iblean platform and its underlying basement. The associated gravity anomaly is interpreted as the southern wedge edge of the Tyrrhenian mantle that splits the subducting Iblean–Pelagian (African) continental slab from an overlying synformal stack of allochthonous thrust sheets. Supplementary materials: Additional data are available at www.geolsoc.org.uk/SUP18594.

WALKING ALONG A CRUSTAL PROFILE ACROSS THE SICILY FOLD AND THRUST BELT

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Contour map of the top of the regional geothermal reservoir of Sicily (Italy)

An integrated review of existing geological and geophysical data – partly acquired during oil and gas exploration – combined with new data provided by deep geothermal studies of selected key areas, was used for the 3D modeling and mapping of the top of the geothermal reservoir developed at a regional scale in Sicily (Central Mediterranean). The resulting 1:500,000 scale map covers the area of the whole Sicily (about 25,700 km2) and is devoted to represent the main input for both the thermal modeling and the evaluation of geothermal potential at a regional scale. As the map indicates the distribution at depth of a likely target for geothermal drilling, it can be also used as a rough indicator of expected drilling cost for geothermal projects. Such a map can be seen as a useful planning tool for any geothermal project, and related exploration to be carried out in the Sicily region in the future.

Middle Miocene–Early Pliocene wedge-top basins of NW Sicily (Italy): constraints for the tectonic evolution of a ‘non-conventional’ thrust belt, affected by transpression

The study of geological evolution of a multiphase orogenic belt is complex, expecially when the tectonic events are superimposed in a coaxial fashion. The Sicilian fold-and-thrust belt represents an interesting case study, as a non-coaxial superimposition of structures is recognizable, owing to large synkinematic clockwise rotations during each of two subsequent compressional events. These rotations involved also the syntectonic basins that developed in the wedge-top depozone. This study aims to constrain the tectono-depositional evolution of the NW Sicily fold-and-thrust belt and the associated wedge-top depozone between the middle Miocene and the early Pliocene. Integrated analyses of stratigraphic, sedimentological and structural field data allow us to better constrain the transition between the two tectonic events. The syntectonic basins developed during the first (late Serravallian–early Tortonian) tectonic event were relatively wide and characterized by marine sedimentation. The onset of the second (latest Tortonian) transpressional event induced localized deformation into the wedge-top depozone and the syntectonic successions were accommodated as basin fill in progressively narrower and laterally discontinuous basins, bounded by transpressional structures. The lateral correlation of the wedge-top successions suggests a latest Miocene regional palaeoslope with a present-day WSW dip, which fits well with the tectonic transport calculated for the early compressional event.

Extensive backthrusting features in the northern Sicily continental margin highlight a late collisional stage of the Sicilian Fold and Thrust Belt

Abstract from 88th Congress of the Italian Geological Society, 2016-09-07 - 2016-09-09, NaplesAbstract from 88th Congress of the Italian Geological Society, 2016-09-07, 2016-09-09, Naplesbook Edited by D. Calcaterra, S. Mazzoli, F.M. Petti, B. Carmina & A. Zuccari doi: 10.3301/ROL.2016.79