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4 F. NIGRO
STRUCTURAL SETTING OF THE SICILY ary basinal carbonatic sequences (Sicanian domain-derived
THRUSTBELT structural units).;
The main tectonié domains characterising the Centrai 8 - the deepest element of the Eastern Sicilian Belt,
Mediterranean, that may be recognised on land and under formed by prevalently Oligocene to Miocene clastic se-
the sea around Sicily (Fig. 2), are (from the south): quences, Messinian evaporites and Pliocene to Pleistocene
basinal sequences ("Gela Thrust System"; Catalano et al.,
- an undeformed, or weakly deformed foreland extend- 1993b.).
ing from north-eastern Tunisia to south-eastern Sicily and
partly inflected below; 9 - the gently deformed Hyblean foreland.
From the top, the geometry ofthe Western Sicily Belt is
- the strongly deformed Sicily Belt, trending E-W from due to the superposition of:
the Egadi Islands to the Malta Escarpment, and northwards l - severa! tectonic units derived of deformation of the
as far as the Southern Sardinia Channel; "pre-Panormide" domain;
2 - a set of tectonic units prevalently consisting of Tri-
- the Kabilias and the Calabrian-Peloritani Are forming assic to Neogene carbonates, derived from deformation of
the submerged Drepano Smt. (Compagnoni et al., 1986) and the Panormide domain;
the Elimi Chain (Beccaluva et al., 1984), interpreted as an 3 - severa! tectonic units made up of Triassic to Neo-
intennediate element in the African Maghrebide-Sicily- gene basinal sequences, derived from deformation of the
Apenninic Belt; Imerese domain;
4 - another set of tectonic units of Triassic to Neogene
-the European-Sardinia Domain (Auzende et al., 1974; prevalently carbonatic sequences derived from deformation
Barberi et al., 1984) thrust over the submerged Kabilo- of the Trapanese domain;
Calabrian domain. 5- severa! tectonic units composed ofMesozoic to Ter-
tiary basinal carbonatic sequences, derived from deforma-
Fig. 2. Schematic tectonic map ofthe Centrai Mediterranean tion ofthe Sicanian domain;
6 - the Meso-Cainozoic defonned foreland (Saccense
Two tectonic piles, derived from the deformation of dif- domain-derived tectonic units);
ferent African palaeogeographic domains, characterise the 7 - the Gela Thrust System.
western and the eastern sectors of the Sicilian Belt (for re- Fig. 3 shows two simplified deep structural sections
cent lithologic columns, with indicated periods oftectonism across the western and eastern Sicily. The structural style re-
see Catalano et al., 1993b). cently recognised in the island is comparable to the thin-
skinned deformational mode!; the overall folds and thrust
The Eastern Sicily Belt consists of several thrust sys- belt show ramp and flat geometries, different duplex levels,
tems made up (from the top) of: some regional-propagated detachment surfaces, and a
marked disharmonic folding. A multiduplex configuration
l - a set of prevalently Hercynian crystalline tectonic has also been recognised in different sectors of the Sicilian
units ofthe Peloritani sector ofthe Calabrian Are; chain (Lentini et al., 1990; Catalano et al., 1993b), as well
as in the surrounding submerged areas (Catalano et al.,
2 - severa! tectonic units of Cretaceous to Paleogene 1993c).
flysch-like sequences (Flysch di Monte Soro); In the deep structural sections (Fig. 3), the main pa-
laegeographic domains-derived tectonic units are repre-
3 - severa! tectonic units of very strongly deformed sented, together with the main "out-of-sequence" low angle
Cretaceous claystones and "Sicilidi Variegated Shales"; reverse faults (<1>), that may be the result of back-stop-iike
processes, probably active since the Langhian (age of se-
4- severa! tectonic units of Oligocene to Miocene fore- quences overlying the back-thrusted "Antisicilidi units").
land siliciclastic turbidites (Flysch Numidico); Out-of-sequence faulting repeated the previous deformed
tectonic complex and might have produced the subsequent
5- some prevalently Triassic to Neogene carbonate tec- superposition of the more external units (e.g. Panormide
tonic units (Panormide domain-derived structural units); units) over the most internai ones (Fig. 3B), as well as the
Trapanese units over the Sicanian units.
6- severa! tectonic units consisting ofTriassic to Neo-
gene basinal sequences (Imerese domain-derived structural OLIGO-MIOCENE KINEMATICS AND
units); THE BACK-STOP MODEL SUPPORT FOR
7 - severa! tectonic units formed by Mesozoic to Terti- THE SICILY BELT
The kinematic history of the Sicilian Maghrebides is
comparable to the thrust envelopment mode! in the litera-
ture. During the Miocene, the collisional processes induced
the deformation of the African domains, expressed by the
activation of some thrust families linking in different de-
