Sedimentology and stratigraphy of the «Piaggine Sandstones» (Cilento, southern Apennines, Italy)

A siliciclastic turbiditic Formation, informally known as «Piaggine Sandstones» of Miocene age, has been investigated in terms of its stratigraphy and sedimentology. The analysed succession is exposed along the north-west side of Mt. Cervati (Cilento, southern Apennines). It represents the most recent depositional event of Mt. Cervati before the arrival of the «allochthonous» nappes. From the study of several stratigraphic-sedimentological sections, it comes out that the «Piaggine Sandstones» can be subdivided into two subunits, i.e. a stratigraphically lower, dominantely pelitic that indicates a sedimentation of lobe-fringe of outer fan and slope deposits of the basin edge (PS1), and an upper, sandy one (PS2), that indicates small turbiditic lobes. The sedimentological characteristics show that these sediments have been deposited in a basin subjected to syn-sedimentary tectonics, as indicated by repeated intra- and extra-basinal slumps, sharp vertical and lateral facies and thickness variations. The «Piaggine Sandstones», resting unconformably on the eroded and deformed substratum, seal a former deformational event of Serravallian age. Therefore, they represent the product of sedimentation in a syn-orogenic basin (piggy-back), Serravallian-Tortonian in age, related with the Toppa del Pràto Fm. in the Alburni Mts., the Raganello Fm. in the Pollino Mt. This depositional site is possibly also related in time with the basin of the Cilento Group. These deposits show a different tectono-sedimentary evolution from the Miocene deposits cropping out in the Maddalena, Matese and Suio Mountains.