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332 A. Sulli / Tectonophysics 324 (2000) 321–336

Fig. 13. NW–SE-trending seismic profile shows, between 8 and 5 s (twt), some strong reflectors interpreted as carbonate platform
tops of deeper thrust which underlie duplexes of interpreted basin-type rocks and tectonic slices of terrigenous deposits (Numidian
or equivalent Flysch roof-complex) (modified after Catalano et al., 1996; Sulli, 1996). Plio-Pleistocene sediments partly cover the
Messinian (M ) reflector. FN, Numidian Flysch; Tb, top of basinal successions; Tp, top of platform carbonates.

of about 6–7 s/twt as confirmed by the multichan- Syn- and post-Messinian low-angle normal
nel seismic line of Fig. 13. In this area the crust faults gave rise to wide basinal areas linked to the
has the greatest thickness (about 35 km) of the opening of the Tyrrhenian sea (Fabbri et al., 1981;
whole chain. Kastens et al., 1988). The Pliocene–Pleistocene
basin filling appears to be deformed by extensional
The chain developing from Egadi to Adventure growth faulting, later affected by tectonic inversion
Bank consists of a 12 km thick fold and thrust (I in Fig. 17). The latter event is possibly related
belt overlying a 25 km thick crust. to a change in the stress field implying compression
along a N–S stress axis (Catalano and Milia,
The main structural features are shown in 1990). Recent high-angle and high-throw normal
Figs. 14 and 15, where only stacks of carbonate faults point to extensional tectonics in the area,
platform units occur. Basin-derived and Numidian maybe due to the crustal isostatic response to the
deposits nappes disappear south-eastwards in the emplacement of the tectonic edifice.
Egadi area.
6. Tectonic evolution
The carbonate ramps are bounded by the Egadi
thrust front that faces the Upper Tortonian fore- In the central Mediterranean, the deformation
deep basins filled by clastic deposits. Also this started after the collision of the Sardinia island
front appears deformed and thrust south-eastward arc with the African margin. Thrusting began in
by a younger deformational event (Fig. 16). the Late Paleogene–Early Miocene, with the
internal imbrication of the Sardinian and
The vergence of the chain, generally south-
eastward directed, was modified by variously dip-
ping post-Messinian thrust planes (Oldow et al.,
1990) and Plio-Pleistocene strike–slip positive
structures.