Unit II extends from 519.8 to 654.5 mbsf and is late Oligocene to Pliocene in age. The sediment is composed of foraminifer-rich clay, silty clay with numerous discrete burrows, diatomaceous silty nannofossil clay, and clayey to sandy nannofossil chalk. Sand and silt laminae are scattered throughout the unit, and thick beds of glauconite occur toward the base. Unit III extends from 654.5 to 663.6 mbsf and is late Eocene in age. Shore-based analyses are likely to improve age resolution for the other sequence boundaries.
Older surfaces tend to become amalgamated in the slope area.
Continued efforts in seismic processing and interpretation, as well as in biostratigraphy, may result in still better estimates. Biostratigraphic resolution is excellent throughout most of the Pleistocene through late Eocene section. Planktonic foraminifers add to the confidence level of biostratigraphic zonation at Site 1073. Where age calibration is possible using planktonic foraminifers, they are compatible with the nannofossil zonations. Provenance changes indicated by changes in the benthic foraminiferal faunas may be associated with relative sea-level changes in the Pleistocene.