Location and migration of Miocene–Quaternary volcanic arcs in the SW Pacific region

We report new Ar–Ar and U–Pb ages from ten rocks in the SW Pacific region. Our results (1) establish a northward Late Miocene Australian plate movement rate of 57 mm/a for the Lord Howe hotspot chain; (2) reinforce the previously established widespread nature of Early Miocene subduction-related volcanism in onland and nearshore northern New Zealand; (3) indicate that leucotonalite xenoliths from Raoul Island are the products of Quaternary Kermadec arc magmatism rather than being Cretaceous–Pliocene basement. A synthesis of available SW Pacific data emphasises that while there is a reasonably complete record of subduction-related volcanism from at least 23 Ma to the present day, the process of back-arc basin formation is highly episodic and asymmetric. Subduction-related arcs stabilised along the Taupo–Kermadec–Tonga arc from 2 Ma to the present, along the Taranaki-Colville-Lau trend from 17–6 Ma and along the Three Kings Ridge–Northland Plateau–Northland trend from 23–18 Ma. South of latitude 25°S, back-arc basin opening occurred during the Early Miocene and Quaternary arc volcanic episodes, but does not appear to have accompanied the 17–5 Ma volcanism.