Kaingaroa Ignimbrite, Taupo Volcanic Zone, New Zealand: evidence for asymmetric caldera subsidence of the Reporoa Caldera

The 0.23 Ma Kaingaroa Ignimbrite represents the only large-scale eruption f rom Reporoa Caldera, Taupo Volcanic Zone, New Zealand. A combination of det ailed volcanology and lithic componentry of the Kaingaroa Ignimbrite and mo rphological and geophysical data on the caldera has constrained the develop ment of Reporoa Caldera. The Kaingaroa Ignimbrite eruption evolved from a single vent during the ini tial stages of the eruption, to a trapdoor caldera with the opening up of f ractures coincidental with regional faults along the eastern margin, from w hich the main part of the Kaingaroa Ignimbrite was erupted. Finally, calder a collapse occurred during the later stages of the eruption. Asymmetric ign imbrite and facies distribution is interpreted as largely resulting from ea stward-directed pyroclastic flows erupted during intially asymmetric calder a subsidence.