Age and statistical properties of the summit palaeosurface of southern Italy

Abstract

Age constrains and statistical properties of the summit palaeosurface of the south-Apennine chain – Calabrian Arc have been investigated with the aims of refining its use as a morphotectonic marker and distinguishing climate and tectonic contributions in landscape evolution. The tops of the mountains of southern Italy are often featured by erosional flat landforms representing the remnants of a wide palaeosurface attributed to the late Pliocene – Quaternary boundary. Apatite fission-track analyses collected in the last years furnished new chronological constrains in terms of its absolute age: this kind of data has been here used in combination with geology and morphotectonics to better define its evolution. On this basis, we infer that both the cooling event and the erosion land surface now preserved at the top of the relief are evidence of the same episode of exhumation.
It is worthy to note that the AFT cluster is comprised between 2 and 3 Ma, as well as mid-Pliocene sediments are the youngest deposit involved in the ancient planation process. Curiously, also the new interpretation of these data in the key of land surface dating suggests that the transition period between the late Pliocene and the early Pleistocene represents the time-span in which the summit palaeosurface developed. Such a regional feature was displaced by the 1.8 Ma regional tectonic stage. Maps of palaeosurfaces derived by geomorphological survey have been compared to those constructed by identifying pixels on the SRTM DEM on the base of their current altitude and slope. The Sila Massif (Calabrian Arc) and the Campania-Lucania segment of the southern Italian Apennines, characterized by quite different geological settings, are chosen as test sites. The statistical properties of the palaeosurface remnants are here interpreted in terms of a common climate-driven fluvial erosion process and different tectonic activities in the two study areas.