Oligocene-to-Early Miocene depositional and structural evolution of the Calabria–Peloritani Arc southern terrane (Italy) and geodynamic correlations with the Spain Betics and Morocco Rif

Abstract

The Calabria–Peloritani Arc southern terrane is a stack of crystalline basement nappes, some of them provided with a widely outcropping Alpine sedimentary cover, sealed by clastics of the Stilo–Capo d’Orlando Formation (SCOF). New field observations in the Stilo area lead to define a Pignolo Formation as a sedimentary cycle predating the emplacement of the uppermost nappe (Stilo Unit) of the tectonic pile. It includes the well-known Lithothamnium and larger foraminifers bearing calcarenites, previously interpreted as a basal member of the SCOF. The biostratigraphic revision of both formations, together with recently published data about other preorogenic deposits, point to a stacking of the whole terrane between the Aquitanian and the middle–late Burdigalian. A comparison between the sedimentary cycles characterising the Calabria–Peloritani southern terrane during the Oligocene–Early Miocene and those almost coeval of the Betic–Rifian internal units highlights their quite similar evolution. Thus it is reliable that both the orogenic belts originated from contiguous paleogeographic realms. These considerations confirm that the present western Mediterranean Chains were originally segments of a continuous orogenic belt disrupted by the opening of the Balearic and Tyrrhenian basins.