Miocene/Pliocene boundary magnetostratigraphy at Capo Sopartivento, Calabria, Itlay

A magnetostratigraphic study at Capo Spartivento (Calabria, southern Italy) indicates that the Miocene/Pliocene boundary lies in the lowest reversed interval (Chron 3r) of the Gilbert Chron. The magnetostratigraphic time frame gives an estimate close to 19 ka for the duration of individual limestone-marl couplets that characterize the lithology. The eight couplets within Chron 3r indicate that the age of the Miocene/Pliocene boundary is about 154 ka older than the age of the reversal at the top of Chron 3r (4.78 Ma). We therefore estimate the age of this boundary as 4.93 Ma, which is 420 ka younger than that given by Berggren et al. and 100 ka older than that given by Zijderveld et al. The first-appearance datums of Globorotalia margaritae and Globorotalia puncticulata are similarly estimated to have ages of 4.66 and 4.15 Ma, respectively, the former being considerably younger than its first appearance in the open ocean.