Improved dating of the Pliocene of the eastern South Atlantic using graphic correlation: implications for paleobiogeography and paleoceanography

Graphic correlation of foraminifer and nannofossil events establishes a high resolution chronology for the Pliocene at Deep Sea Drilling Project Site 532. Coarsely sampled magnetic inclination data are reinterpreted to indicate a complete Pliocene section. The age model suggests mean accumulation rates of 9.5 cm 10-3 yr for the first half of the early Pliocene and 5.8 cm 10-3 yr throughout the later part of the early Pliocene - early Pleistocene. Major upwelling began at the location of Site 532 at 3.2 Ma. Time series analysis indicated a 41 ky cyclicity to the CaCO3 record between 2 and 4.5 Ma. Data support ages of 1.9 Ma for the first appearance of Globorotalia truncatulinoides and approximately isochronous southern hemisphere first appearances for Globorotalia crassaformis (4.70 Ma), Globorotalia puncticulata (4.77 Ma), and Globorotalia inflata (3.68 Ma). -Author