Pliocene-Pleistocene Composite Reference Section for Southern Ocean Diatom Biostratigraphy

Biostratigraphic Composite Reference Section for Pliocene and Pleistocene
diatoms in Southern Ocean sediments. 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.