Paleoceanographic significance of late Miocene to early Pliocene planktonic foraminifers at Deep Sea Drilling Project Site 609.

Abstract

The planktonic foraminifers in 124 samples from Holes 609 and 609B have been analyzed quantitatively to see whether oceanographic events in the late Miocene and early Pliocene (6.5-4.0Ma) are reflected in the distribution of individual species. Major changes in sea-surface temperature and bottom-water circulation are postulated. A cool interval peaking at around 6.2Ma was followed by climatic fluctuations before a general warming in the Pliocene. Intense dissolution of CaCO3 is inferred to have resulted from the presence of Antarctic Bottom Water, and an influx of less aggressive N Atlantic Deep Water is indicated at the actual boundary. These climatic and oceanographic changes are tentatively linked to the Messinian salinity crisis in the Mediterranean.-from Authors