Calabrian and Ionian: A proposal for the definition of Mediterranean stages for the Lower and Middle Pleistocene.

The need to standardise stratigraphical subdivisions of continuous marine sedimentary successions that outcrop for hundreds metres, using clearly defined points fixed in the field is strongly felt. A proposal is presented here to formalize regional stages for the Lower Pleistocene (Calabrian) and for the Middle Pleistocene (Ionian) in Italy. The sections are well exposed, carefully investigated using multiple criteria (an integrated stratigraphical approach) and located in the central part of the Mediterranean. This area is recognized worldwide as a classical region for the Neogene and the Pleistocene sequences. The terrestrial record is directly correlated with the deep-sea record, as determined from ODP Sites 653 (Tyrrhenian Sea), 963 (Sicily Channel) and 964 (Ionian Sea) from the central Mediterranean. The present formal proposal is consistent with the INQUA and ICS decision to define and correlate the Plio/Pleistocene boundary (GSSP at Vrica) within the Olduvai Subchron, at 1.81 My, the Lower/Middle Pleistocene boundary at the Matuyama/Brunhes reversal at 0.78 My and the Middle/Upper Pleistocene boundary with the base of MIS 5, approximately 0.13My. The present proposal also is consistent with the call for stage unit stratotypes that emphasize both the physical content of a stage and its boundaries (Hilgen et al., 2006).