Florida State University, United States

Calcareous Nannofossils are widely utilized in biostratigraphic studies of Cenozoic sediments. In recent years large datasets have been acquired, and several bioevents showed to be unreliable when correlated over distant areas. New biostratigraphic investigations of middle Eocene-upper Oligocene deep-sea cores have highlighted problematic areas in the currently used calcareous nannofossil zonal schemes for the Southern Ocean. Quantitative analysis on sediments from seven ODP (Ocean Drilling Program) sites from this area, characterized by abundant, diverse, and moderately to well-preserved nannofloral assemblages, have enabled a revision of the existing zonation for the Southern Ocean, and the development of a high-resolution zonal scheme. Eleven zones and six subzones are introduced or emended to replace the ten zones and two subzones of the Wei and Wise (1990a) and Wei and Thierstein (1991), with the identification of several new biohorizons. New age calibrations are provided improving regional correlations and evaluating the reliability of the identified events for supraregional correlations. Comparisons are made between the proposed zonation and the existing schemes, both on nannofossils from different geographic areas, and on foraminifers from southern high latitudes. Abstract Copyright (2012) Elsevier, B.V.