Extensional deformations during Neogene chain building in Sicily

Fabrizio Nigro(*), Gaetano Salvaggio(**), Pietro Renda(*), (**) & Rocco Favara(*)
(*) Istituto Nazionale di Geofisica e Vulcanologia, via U. La Malfa, 153 - 90146 Palermo. E-mail: f.nigro@pa.ingv.it - p.renda@pa.ingv.it - r.favara@pa.ingv.it (**) Dipartimento di Geologia e Geodesia dell'Università, viaArchirafi, 26 - 90123 Palermo. E-mail: salvaggio.gaetano@libero.it

In the Madonie-Nebrodi Mts (Northern Sicily belt) both Mesozoic carbonate platform/basin-derived deformed successions and Neogene foredeep deposits outcrop. Thrust sheets piled-up southwards in thin-skin piggy-back sequence. The chain building process began during the Oligo-Miocene. The syntectonic deposits involved in the compressional tectonics give evidence that syn-sedimentary extensional faults developed during fold nucleation and amplification. Syn-sedimentary extensional faults affect the foredeep strata at different stratigraphic levels, which are bounded by unconformities. Normal faults and bedding show constant cut-off relationships and are progressively tilted youngwards as the effect of thrust-related folding. Since their formation, these normal faults have locally interacted with the thrust geometry by means of positive inversion within the older strata and with physically connected to reverse faults crosscutting the succession youngwards.

Syn-sedimentary faults, faulting-folding interaction, positive inversion, Sicily.