Argon geochronologic data from New Zealand's Ruapehu and Tongariro Volcanoes used to illustrate geochronology systematics

Understanding the eruptive histories and petrogenetic models that underpin hazard assessments at active volcanoes typically requires high-precision ages for late Pleistocene to Holocene lava flows. These data vary in quality, typically related to textural and chemical variations in lava flow samples. These samples were part of an existing 40Ar/39Ar dataset for andesitic-dacitic rocks from Ruapehu and Tongariro volcanoes, Aotearoa New Zealand, that were interrogated with new microanalytical data to identify the optimal groundmass material for age determination.