Late Pliocene–Quaternary Arc Volcanism at the Southern Limit of the Hikurangi Subduction Zone: Revised Chronology of the Taranaki Peninsula, New Zealand

Igneous centres across the Taranaki Peninsula represent the southwestern limit of arc volcanism associated with the Tonga–Kermadec–Hikurangi subduction system. Taranaki Maunga, the youngest and largest of three andesitic stratovolcanoes, dominates the geomorphology of the Taranaki Peninsula along with the eroded remnants of the Kaitake and Pouakai edifices. Beneath the peninsula, the ring plain built by Taranaki and its predecessors lies on an angular unconformity cut into Pliocene marine strata. Across the peninsula, surficial volcanic and pyroclastic rocks, which rarely extend more than a few hundred metres below sea level, are intersected by petroleum wells. Using well cuttings and 40 Ar/ 39 Ar dating, we refine the chronology of volcanism across the Taranaki Peninsula. Hornblende from 14 igneous samples yields 40 Ar/ 39 Ar ages ranging from ca. 2.9 to 0.15 Ma. Two western samples (2.895 and 2.291 Ma) are older than exposed Sugar Loaf Andesite (ca. 1.8 Ma). Three samples from beneath the Maitahi Formation, surrounding Kaitake and Pouakai (previously dated between 0.6 and 0.2 Ma), returned ages of 0.932, 0.608 and 0.471 Ma. Six samples from near the base of the ring plain ranged from 0.463 Ma in the Te Kiri North‐1 to 0.333 Ma in Kapuni‐15.