New petrological, geochemical, and geochronological perspectives on andesite-dacite magma genesis at Ruapehu volcano, New Zealand

Time-composition relationships in eruptive sequences at composite volcanoes can show how the ongoing intrusion of magmas progressively affects the lithosphere at continental convergent margins. Here, new whole-rock and microanalytical major and trace element data from andesite-dacite lava flows are integrated with previous studies and existing isotopic data, and placed within the framework of a high-resolution chronostratigraphy for Ruapehu volcano (southern Taupo Volcanic Zone, New Zealand). The geochemical evolution of lavas erupted over the ~200 kyr lifetime of the exposed edifice reflects variable degrees of fractionation and systematic changes in the type of crustal assimilation in the Ruapehu magma system. Lavas erupted from ~200-150 ka have previously been distinguished from those erupted