Integrated strontium isotope stratigraphy and biochronology in the upper Pliocene and Pleistocene of DSDP Site 132 (western Mediterranean)

Planktonic foraminifer shell samples from the upper Pliocene and Pleistocene sequence of the DSDP Site 132 (Tyrrhenian Sea) provide evidence for a general increasing trend in the seawater 87Sr/86Sr isotopic ratios and suggest the applicability of the high-resolution oceanic curves of Sr isotope variations in the land-locked Mediterranean basin. However, a possible exception is detected in the interval between 0.8 and 0.3 Ma, where ratios lower than coeval oceanic values are recognised. The planktonic foraminiferal biostratigraphy and biochronology of this site are consistent with previous Mediterranean studies. The first occurrences (FOs) of Beella digitata, Orcadia riedeli and Globigerina bermudezi, observed in the Pleistocene interval of site 132 succession, are rarely recorded in Mediterranean sections. These bioevents however are easily recognized in several oceanic sequences in the same stratigraphic position; consequently, they can be used in the Mediterranean biostratigraphy.