Isothermal plateau fission‐Track age for a paleomagnetic excursion in the Mamaku Ignimbrite, New Zealand, and implications for Late Quaternary stratigraphy

Mamaku Ignimbrite, the youngest of the large, welded ignimbrite sheet-forming eruptions from the Taupo Volcanic Zone in New Zealand, is dated at 230±12 ka by the isothermal plateau fission-track (ITPFT) method on glass. This age is older and more precise than that indicated by previous studies, requiring the revision of loess/paleosol coverbed chronologies. The eruption occurred during a paleomagnetic excursion allowing the ignimbrite to be easily distinguished from other eruptive events by paleomagnetic methods. This excursion is one of the few such events recorded in igneous rocks in the Southern Hemisphere, may be widely recorded in New Zealand, and is now temporally well constrained.