PLANKTIC FORAMINIFERAL FAUNAL TURNOVERS IN THE SUBTROPICAL PACIFIC DURING THE LATE PALEOCENE TO EARLY EOCENE

Planktic foraminiferal analysis of sedimentary samples at 25-cm interv als (81 k.y.) at DSDP Site 577 provides a high resolution data base fo r deep-sea biostratigraphy and faunal changes during the late Paleocen e to early Eocene. There are three major faunal turnovers, each of whi ch occurred over a time period of 200 to 400 k.y., near the P3a/P3b, P 6a/P6b and P8/P9 boundaries. These turnovers are characterized by rapi d changes in species richness, large numbers of first and last appeara nces, and significant changes in the relative abundances of species. A chronological sequence of datum levels and faunal events of foraminif era tied to magnetostratigraphy provides biostratigraphic control at 1 m.y. intervals for the late Paleocene to early Eocene, with faunal an d isotopic events near the Paleocene/Eocene boundary providing isochro nous stratigraphic markers.