The Valle di Manche section (Calabria, Southern Italy): A high resolution record of the Early-Middle Pleistocene transition (MIS 21-MIS 19) in the Central Mediterranean

The on-land marine Valle di Manche section (Crotone Basin, Calabria, Southern Italy), one of the candidates to host the GSSP of the Middle Pleistocene (“Ionian”) Stage, preserves a manifold record of independent chronological, paleoclimatic and stratigraphic proxies that permit a straightforward correlation with marine and terrestrial reference records at the global scale. In particular, the section holds an excellent record of the Matuyama-Brunhes magnetic reversal, which occurs in the midst of Marine Isotope Stage (MIS) 19. We report on a complete revision of the section that improves dramatically the available dataset, especially in the stratigraphic interval straddling the Lower-Middle Pleistocene boundary. Our benthic δ18O record provides evidence that the Matuyama-Brunhes transition, the stratigraphic position of which is marked by a prominent tephra (the “Pitagora ash”), occurred during full MIS 19, in agreement with many records worldwide. We obtained an age of 786.9 ± 5 ka for the Matuyama-Brunhes magnetic reversal and pinpointed the paleomagnetic transition of to a 3 cm-thick interval, indicating that the event was very fast. Since the section fulfills all the requirements to host the GSSP of the Ionian Stage, we propose that the boundary should be placed at the base of the “Pitagora ash”, ca. 12.5 cm below the midpoint of the Matuyama-Brunhes reversal.