Te Punga, M.T. 1981 The Pliocene/Pleistocene boundary and the Nukumaruan Stage, New Zealand. Lower Hutt: New Zealand Geological Survey. Report NZGS 96 19 p.
Abstract: In the proposed stratotype for the Pliocene / Pleistocene boundary in the Vrica section, Calabria, Italy preliminary radiometric dates for the Vrica ash, close to the suggested boundary, are spread between about 2 m.y. and 2.5 m.y. There are conflicting opinions concerning the magnetostratigraphy of the Vrica section. At Santerno basal Pleistocene beds containing a volcanic ash dated at 2.1 m.y. have been assigned to the Reunion. At Stirone the Pliocene / Pleistocene boundary is apparently older than the beginning of the Olduvai subchron (1.87 m.y). ''Interpolation of magnetic reversal age'' suggests that the boundary could be close to the end of the Olduvai, about 1.7 m.y. From fission-track dates it is calculated that the Nukumaruan Stage, Wanganui Basin, New Zealand began about 2.08 m.y. ago. At Mangaopari Stream, East Coast Basin, a date of about 2 m.y. has been estimated for the beginning of this stage from reinterpretation of the correlation of the paleomagnetic reversals. A date of about 2 m.y. for the Pliocene / Pleistocene boundary would place it in the pre-Nukumaruan Waitotaran Stage. A date of about 1.7 m.y. would place the boundary near the middle of tne Nukumaruan Stage. The last appearances of Cyclococcolithus macintyrei (1.62 m.y.) and Helicosphaera sellii (1.3 m.y.) in the Nukumaruan can be used for direct correlation between Vrica and New Zealand. It is recommended that, until the Pliocene / Pleistocene boundary stratotype is officially designated in Italy, the long established practice of placing the Pliocene / Pleistocene boundary at the base of the Nukumaruan Stage be continued.