Chronology of the marine terraces of the Crotone Peninsula (Calabria, southern Italy) by means of infrared-stimulated luminescence (IRSL)

Abstract

The Crotone Peninsula (southern Italy) preserves a well developed flight of marine terraces generated by the interplay of uplift of the Calabrian arc and late Quaternary eustatic oscillations. Good chronologic control on the formation of these raised geomorphic features would help constrain regional tectonic and stratigraphic models. However, precise age assignment and correlation of the individual terraces is hampered by lack of material suitable for radiometric dating.With the goal of improving the resolution of the chronology of the terraces, nine samples were collected from four stratigraphically distinct terraced units and dated with the infrared-stimulated luminescence (IRSL) technique applied on feldspar grains. The obtained ages are consistent with the stratigraphic arrangement of the terraces, with samples from higher terraces older or overlapping in age with those from lower terraces. Three samples from the highest (Cutro) terrace indicated a minimum age ≥ MIS (Marine Isotope Stage) 7. Two samples from the second of the four examined terraces, which is generally correlated with MIS 5.3, gave ages that correlate instead with MIS 5.5 and 5.1, revealing more internal complexity and tectonic disruption than previously inferred from this terrace. Luminescence dating was applied for the first time to the deposits of the Capo Colonna terrace, with results indicating a MIS 5.1 age. Finally, one sample from the lowermost (Le Castella) terrace confirmed the preservation of raised marine deposits from MIS 3, a relatively uncommon finding for the Mediterranean region.These results highlight how IRSL dating can contribute to the development and refinement of a chronostratigraphic context for a flight of marine terraces and, ultimately, to a clearer understanding of the combined tectonic and eustatic controls affecting the morphodynamic evolution of a marine coastal sector. More specifically, they confirm the persistence of relatively high average uplift rates (on the order of 1 mm/yr) over the last two glacial cycles in the Crotone Peninsula and the important role of a local component of tectonic and deformative displacement superimposed on the regional uplift.