Pliocene-Pleistocene Composite Reference Section for Southern Ocean Diatom Biostratigraphy

The new quantitative biostratigraphic model incorporates records of 78 diatom taxa, 29 paleomagnetic reversals, and two radiometrically dated ash layers from 27 Plio- Pleistocene sections in the Southern Ocean and around the Antarctic continental margin. A CONOP analysis of this data set yields precise ages for biostratigraphic events as old as 8 Ma, bracketing event ages to within an average of 0.2 Ma.

The model provides up to an order of magnitude greater temporal resolution than traditional zonal biostratigraphic models, identifies many new potentially useful data, and calls into question the reliability and isochroneity of some commonly utilized zonal marker events. The majority of age assignments for current zonal events are within the range of published age estimates; others differ from previous estimates by 2 million years.