Cenozoic nannofossils from the Exmouth Plateau, eastern Indian Ocean

Six sites (759-764) were drilled on the Exmouth Plateau during Ocean Drilling Program Leg 122. Nannofossilrich Cenozoic sediments were recovered at all six sites, reflecting the open-ocean conditions that prevailed over the Exmouth Plateau during the Cenozoic. Calcareous nannofossils are abundant, diverse (250 different species identified), and generally well preserved throughout the composite lower Paleocene to Quaternary section. The diversity and preservation of nannofossils permits a high degree of stratigraphic resolution at each site. Site 762 on the central part of the Exmouth Plateau contains an almost unbroken Cenozoic record (only Miocene Zones NN3, NN8, and NN10 are missing). This site may prove to be a useful Cenozoic biostratigraphic and biomagnetochronologic reference section for the eastern Indian Ocean.

(Table 1) Carbon- and oxygen-isotopes for bulk sediment carbonate at DSDP Holes 86-577 and 86-577A

We have obtained a detailed carbon-isotope stratigraphy of the Paleocene sections recovered from Deep Sea Drilling Project (DSDP) Holes 577 and 577A. This 13C record is useful in stratigraphically correlating the two holes and in interpreting the magnetostratigraphic data. Comparison with the published data for Site 527 (Southeast Atlantic Ocean) shows that 13C stratigraphy is also valuable for long-distance correlation.