Range chart of calcareous nannofossils in sediment core CRP-2A (Table 1)

These depauperate assemblages lack most of the biostratigraphic index fossils for the Oligocene, but do provide two datum that aid in constraining the age of the section: the last appearance datum (LAD) of Dictyococcites bisectus (23.9 Ma) at 149.28 mbsf and the LAD of Chiasmolithus altus (26.1 Ma) at 412.25 mbsf.

Calcareous nannofossil assemblages stratigraphically below c. 440 mbsf contain conspicuous evidence of reworking of older (late Eocene) specimens that renders age determination difficult.