Tectono-sedimentary constraints to the Oligocene-to-Miocene evolution of the Peloritani thrust belt (NE Sicily)

The Peloritani thrust belt belongs to the southern sector of the Calabrian Are and is formed by a set of south-verging tectonic units, including cryst alline basement and sedimentary cover (from the top: Aspromonte U.; Mela U. ; Mandanici U.; Fondachelli U.: Longi-Taormina U.), piled up starting from Late Oligocene. At least two main terrigenous elastic formations lie with c omplicated relationships on top of the previous units: the Frazzano Fm (Oli gocene) and the Stilo-Capo, d'Orlando Fm (Late Oligocene?-Early Miocene), a s syn-to-post-tectonic deposits. These elastic deposits have different char acteristics, in space and time, representing or flysch-like sequences invol ved in several thrust events (Frazzano Fm) or molassic-like sequences (Stil o-Capo d'Orlando Fm), which unconformably overlie the tectonic units. In the present paper we describe a kinematic model of the progressive forel and migration of the Peloritani thrust brit. starting from Oligocene, carry ing piggy-back basins and incorporating foredeep deposits, recognised in th e Frazzano-Stilo-Capo d'Orlando terrigenous successions. In general. the facies and structural observations on the overall Oligo-Mio cene elastic sequences, outcropping in the Western Peloritani Mts, indicate : (a) the distal character of the Frazzano, Fm; (b) a complex group of terr igenous facies of the Stilo-Capo d'Orlando Fm, with lateral-to-vertical org anisation, characterised by a distal-to-proximal-to-distal facies trend; (c ) facies analogies of the basal portions of the Stilo-Capo d'Orlando Fm wit h the Frazzano Fm; id) the involvement of the Frazzano Fm in lowermost and more external thrusting, and of the basal (Late Oligocene?) distal Stilo-Ca po d'Orlando facies in the higher and inner thrusting during the early stag es of deformation; (e) the involvement of the proximal Stilo-Capo d'Orlando facies in the tectonic edifice during the Early Miocene deformation; (f th e generally unconformable stratigraphical contacts of the higher proximal-t o-distal (Early Miocene) Stilo-Capo d'Orlando facies on the constructing mo bile belt; and (g) the presence of various thrust-faults, distinguished in a sequential order. The collected data allow us to hypothesise that the Oligo-Miocene tectono-s edimentary history was characterised by a foredeep with a deforming interna l flank, probably lying in onlap on the constructing tectonic edifice (Fraz zano-lower Stilo-Capo d'Orlando Fms), and then deformed and covered by a pi ggy-back like sequence (middle-upper Stilo-Capo d'Orlando Fm), which was su bsequently also deformed. The tectono-sedimentary evolution of the Pelorita ni belt has been probably developed through a progressive migration towards the foreland of a foredeep-compressional front couple and the chain body. The thrust stack progressively incorporates terrigenous foredeep deposits a nd in turn carried piggy-back basins. (C) 1999 Elsevier Science B.V. All ri ghts reserved.