Raimondo Catalano

Paleogeography and structure of the central Mediterranean: Sicily and its offshore area

Abstract The geology of the mainland and offshore of Sicily is illustrated by a few geologic sections and seismic profiles across the late Cenozoic orogenic belt of central and western Sicily and across the Sardinia Channel and Sicily Straits. This belt is the result of several tectonic events. Deformation involved mainly the sedimentary cover of the old African continental margin characterized by a broad basinal domain, flanked along its external (southern) margin by a shallow-water carbonate platform attached to Africa in the Triassic. Compressional deformation started in the more internal basinal rock assemblages overlying a thinned crust. The most important structural characteristic of the early phase of thrusting is the duplex pile forming the bulk of the chain in Central Western Sicily. The structure consists of a basal allochthon, made up of Permian to Middle Triassic layers, an intermediate duplex wedge, composed of competent Mesozoic carbonates, and a roof complex, including Upper Mesozoic-Lower Tertiary less competent rocks. Large-scale clockwise rotation of the thrusts accompanied transpressional movements in the hinterland during the Pliocene. Right oblique reverse faults modified the previous tectonic contacts between the allochthons in the hinterland zones. Contemporaneous south-directed imbrications affected the southern external areas, progressively incorporating foreland and piggyback basins. Development of the Gela Thrust System appears to be linked to the transpressional event; its accretion is also related to contemporaneous underthrusting at deeper levels of Mesozoic carbonate substratum. The older buried thrust sheets were pushed up to the surface breaching the deformed Tertiary cover of the Gela TS. Northwards in the belt post-Messinian normal growth faults opened half graben whose sedimentary fill underwent structural inversion. Alternation of extension and compression tectonics characterizes the Sicilian continental margin in the last million years.

Permian circumpacific deep-water faunas from the western Tethys (Sicily, Italy)—new evidences for the position of the Permian Tethys

Abstract Circumpacific deep-water faunas, characterized mainly by radiolarians, paleopsychrospheric ostracods and conodonts, were found in the early, middle and late Permian deposits pertaining to the Sicanian paleogeographic domain of western Sicily, near the western end of the Eurasiatic Tethys. Similar Permian deep-water faunas are known from the Phyllite Unit of Crete and from Oman in the latter area partly above oceanic crust. All these occurrences indicate the presence of a late Paleozoic Tethys ocean immediately north of Gondwana.

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.

Interference between shallow and deep-seated structures in the Sicilian fold and thrust belt, Italy

Abstract: The fold and thrust belt in western Sicily is characterized by the presence and interference of shallow and deep-seated compressional structures, which were generated and developed at different structural levels. The shallow structures consist of imbricated thrusts and asymmetric folds, with a typical wavelength of 2 km, involving relatively thin deep-water units. These units are superimposed on thick platform carbonate units, along a wide and originally almost flat floor thrust. The axial trend of the folds is variable, as multi-phase folding often occurred, producing a characteristic interference pattern, reflecting continuous variations of the apparent transport direction during the emplacement (i.e. rotation of the allochthonous thrust sheets). The deep-seated structures consist of large, double-verging pop-up structures, with a typical wavelength of 5–10 km, involving thicker platform carbonate successions. The deep-seated structures are characterized by large folds, with vertical to overturned limbs, caused by high-angle, transpressive ramps that reactivated previous (i.e. Mesozoic) synsedimentary normal or transtensional faults. The floor thrust of the shallow structures was passively deformed by the subsequent growth of the underlying, younger deep-seated structures. Large clockwise rotations of the tectonic units occurred during the compressional deformation, and the amount of rotation is apparently related to the timing and amount of the tectonic transport.

Relationships of Algae with Depositional Environments and Faunal Assemblages of the Panormide Carbonate Platform, Upper Triassic, Northwestern Sicily

In northwestern Sicily large bodies of Triassic carbonate rocks crop out. They display several lithofacies corresponding from shelf to basin environments. Facies analysis during the last three years has allowed the differentiation and the mapping of different lithofacies (Abate and Catalano, 1974; Catalano et al., 1974a, b).

The structure of western Sicily, central Mediterranean

Western Sicily is part of the Sicilian chain, a sector of the SE-verging Alpine orogenic belt in the central Mediterranean. Interpretation of seismic reflection profiles, boreholes and recent inland geological data, have enabled us to assess the deep structural grain. A wedge of flat-lying Mesozoic–Miocene carbonate and terrigenous rocks (pre-Panormide nappes) is superimposed on NW-trending, 7–8 km thick, Mesozoic–Paleogene carbonate thrust ramps (Trapanese units), arranged in two structural levels extending from the Tyrrhenian coast to western offshore Sicily. Upper Miocene to Pleistocene terrigenous strata, often deformed, fill syntectonic basins above the thrust pile. The main tectonic transport of the thrust pile, developing from Early Miocene to Early–Middle Pleistocene times, was towards the east and southeast. Initial stacking and deformation of the pre-Panormide allochthon is bracketed between Early and Late Miocene. The Late Miocene–Early Pleistocene underthrusting of the Trapanese–Saccense units, that acted through more recent deep-seated thrusts in the carbonate platform layer, induced late stage refolding and further shortening in the early emplaced pre-Panormide nappe. Previously formed structures appear to have been dissected or reactivated by a right oblique transpression during the Late Pliocene–Pleistocene. The geometry of the carbonate bodies opens new potential perspectives on the existence of structural traps, but the uncertainties of source rock occurrence remain.

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

.....................................................................8 摘要 ............................................................................10 Program Summary ....................................................11 First Day .................................................................11 Second Day .............................................................11 Third Day ................................................................12

Interplay of extension and compression in basin formation: introduction

This volume contains a collection of papers on the interplay of extension and compression in basin dynamics presented at the 4th annual workshop of the International Lithosphere Project Task Force “Origin of Sedimentary Basins” in Benevento, Italy, 25 September-l October 1993. Previous workshops of the ILP Task Force have been held in Rueil Malmaison, France (19901, in Matrahaza, Hungary (1991), on the rim of the Pannonian basin, and in Sundvollen, in the Oslo rift (1992). Meeting reports have been published in a number of special volumes and papers (Cloetingh et al., 1993a, b, 1994; Cloetingh, Sassi and Task Force Team, 1994). The 5th Task Force meeting, focusing on basin extension and strike-slip tectonics was held in the Dead Sea rift, Israel, 29 September-5 October, 1994. A selection of papers presented at the 5th Task Force workshop will be published in a forthcoming special volume of Tectonophysics. The 1995 workshop has taken place in the southern Pyrenean foreland basin to examine the relationships between tectonics and eustasy in foreland/fold-and-thrust belts. The emphasis of the Benevento workshop was on

Timing of the emergence of the Europe–Sicily bridge (40–17 cal ka BP) and its implications for the spread of modern humans

Abstract The submerged sill in the Strait of Messina, which is located today at a minimum depth of 81 m below sea level (bsl), represents the only land connection between Sicily and mainland Italy (and thus Europe) during the last lowstand when the sea level locally stood at about 126 m bsl. Today, the sea crossing to Sicily, although it is less than 4 km at the narrowest point, faces hazardous sea conditions, made famous by the myth of Scylla and Charybdis. Through a multidisciplinary research project, we document the timing and mode of emergence of this land connection during the last 40 kyr. The integrated analysis takes into consideration morphobathymetric and lithological data, and relative sea-level change (both isostatic and tectonic), resulting in the hypothesis that a continental land bridge lasted for at least 500 years between 21.5 and 20 cal ka BP. The emergence may have occurred over an even longer time span if one allows for seafloor erosion by marine currents that have lowered the seabed since the Last Glacial Maximum (LGM). Modelling of palaeotidal velocities shows that sea crossings when sea level was lower than present would have faced even stronger and more hazardous sea currents than today, supporting the hypothesis that earliest human entry into Sicily most probably took place on foot during the period when the sill emerged as dry land. This hypothesis is compared with an analysis of Pleistocene vertebrate faunas in Sicily and mainland Italy, including a new radiocarbon date on bone collagen of an Equus hydruntinus specimen from Grotta di San Teodoro (23–21 cal ka BP), the dispersal abilities of the various animal species involved, particularly their swimming abilities, and the Palaeolithic archaeological record, all of which support the hypothesis of a relatively late land-based colonization of Sicily by Homo sapiens.

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.