DYNAMICS and ACTIVE PROCESSES - International Lithosphere ...

and Italy in the centre, and the Ionian abyssal plain and Eastern Mediterranean Ridge in the
east. For instance, Late Cretaceous to Paleogene pre-collisional inversions are well
documented in the autochthonous foreland in the Saharan Atlas, in the Sicilian Channel and
the Ragusa Plateau, where they predate the development of the overlying Miocene flexural
basin. Intra-Tortonian inversions are also documented from Sfax in Tunisia to the Sicani
Mountains in Sicily, as well as in the deep offshore Ionian Basin. Post-suture transpression
accounts also for late inversions of the underthrust foreland in the Southern Apennines
(Tempa Rossa and Monte Alpi subthrust prospects), northern Sicily (Panormide-Imerese
nappes anticline), as well as beneath the Tellian allochthon in Algeria (Bibans and
Constantinois tectonic windows), whereas transtension and strain-partitioning near the backstop
have locally led to the development of thrust-top pull-apart basins in the Chelif area
(Algerian Tell), San'Archangelo Basin (Southern Apennines), as well as on top of the
Mediterranean Ridge off the western coast of Peloponnesus.
Whereas slab pull or slab retreat are known to account for foreland flexure and subsidence,
with deposition and preservation of deep water series in Neogene foredeeps of the
Maghrebides, Sicily and Apennines, as well as for the present deep water environment of the
Eastern Mediterranean, slab detachment and further dynamic topography linked to
asthenospheric rise beneath the Algerian and Tyrrhenian basins have already led to rapid
uplift and exhumation of the former Tellian, Sicilian and Apenninic foredeeps.
Ultimately, recent seismic imagery and focal mechanisms help also to document the recent
development of north-verging thrust faults at the toe of the continental slope from North
Algerian to North Sicilian margins, thus accounting for a double verging orogen, both the
Algerian Basin and Tyrrhenian Sea now behaving as retro-arc foreland basins with respect to
currently active African margin.
Because recent oil and gas discoveries have been made in the Southern Apennines and Sicily,
the knowledge of these various structural styles, source rock distribution and timing of their
maturation should be used as useful analogues when ranking the petroleum potential of early
foreland closures versus late subthrust prospects in the yet under-explored areas of the
Algerian foothills (Tell) in the west, and to limit also the exploration risk in the deep Ionian
offshore and Eastern Mediterranean Basin in the east.
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