Age constraints on the proposed Plio-Pleistocene boundary stratotype at Vrica, Italy

Estimates1-4 of the age of the stratotype Plio-Pleistocene boundary in Italy range from 1.65 to 2.5 Myr. We aim here to clarify this dating confusion, and we present new radiometric data on ashes from the proposed stratotype section, Vrica, Italy which indicate that the Plio-Pleistocene boundary must be less than 2 Myr old. Biostratigraphical criteria - The first appearance datums (FADs) and last appearance datums (LADs) of plank-tonic foraminifera and calcareous nannoplankton tied to the magnetic reversal chronology - Suggest that this boundary may be nearer to 1.7 Myr. Attempts to make the boundary far older than this are without basis. ?? 1982 Nature Publishing Group.