Planktonic foraminiferal oxygen and carbon isotope analyses from Tyrrhenian Sea Ocean Drilling Program (ODP) Site 653 provide a continuous record of the Pliocene-Pleistocene paleoceanographic history of the Mediterranean. Long-term trends in oxygen isotopes primarily reflect changes in global climatic conditions, with a more local or regional signal superimposed on this record. For example, significant enrichments in 18O due to decreases in surface water temperature and/or increases in continental ice volume occurred at 3.1, 2.7, 2.1, 1.6, and 0.4 Ma.In contrast to most open-ocean results, the early Pliocene 6lsO record of Site 653 exhibits high-amplitude fluctuations indicative of very unstable climatic conditions in this region. Another unique aspect of this Mediterranean d18Orecord is the pronounced cooling at the Pliocene/Pleistocene boundary. The carbon isotope record for Site 653 also exhibits high-amplitude variability throughout the Pliocene-Pleistocene. This variability most probably reflects changes in the carbon isotopic composition of the source of Mediterranean surface waters.

Supplement to: Thunell, Robert C; Williams, Douglas F; Tappa, Eric; Rio, Domenico; Raffi, Isabella (1990): Pliocene-Pleistocene stable isotope record for Ocean Drilling Program Site 653, Tyrrhenian Basin: implications for the paleoenvironmental history of the Mediterranean Sea. In: Kastens, KA; Mascle, J; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 107, 387-399