Calcareous nannofossil biostratigraphy of ODP Leg 127 sites

Nannofossils occur sporadically at all sites, and allow recognition of seven zones and two subzones; four zones in the Holocene to the uppermost Pliocene, and three zones and two subzones in the middle to lower Miocene. Forty-eight nannofossil species are recognized in 95 of the 808 irregularly-spaced samples taken from all the sites.

The nannofossil assemblages in the Miocene are more diverse than those in the Holocene to Pliocene sedimentary interval. The greater diversity and the presence of warm-water taxa, such as Sphenolithus and discoasters in the upper lower Miocene to lower middle Miocene, suggest a relatively warm and stable surface-water condition, attributed to an increased supply of warm water from the subtropical western Pacific Ocean.