Sequence of deformation in the sicilidi units (northern sicilian chain)

The foredeep deposits of Northern Sicily, indicated as Sicilidi units, have undergone different deformations' since Oligocene time. The resulting tectonic Structures, analysed in several outcrops in the Eastern Madonie Mts, are 1 cm-to- 100 m in scale and are similar to the larger structures forming the Sicily belt, allowing for scale extrapolation. Also the overprinting relationships of the minor structures recorded in the so-called Tufiti di Tusa reflect the sequence of fault activation which determined the present-day geometry of the tectonic units, suggesting that the tectonic evolution of the foreland basin developed during the stacking of the Maghrebide fold-and-thrust belt. The overprinting relationships between the mesoscopic structures indicate that the flysch-like Succession (Tufiti di Tusa Fin. auct.) experienced layer-parallel extension and sediment compaction, followed by thrusting, low-angle normal faulting and renewed compression/transpression. The earlier episode of extension is related to the tectonic regime which affected the foredeep ahead of the thrust front during the Oligocene. Compression, in places represented by fault reactivation and inversion, reflects the foredeep deformation, progressively incorporated into the belt during the Miocene. The second event of extension overprints folding and faulting, in places inducing negative inversion of the contractional structures during the Late Miocene, and is related to chain collapse on reaching supercritical wedge taper conditions. The transpressional neotectonic structures reflect the shear zone which has affected the Southern Tyrrhenian margin since the Pliocene.