New Zealand Journal of Geology and Geophysics abstracts

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

S. W. BERESFORD*
J. W. COLE

Department of Geological Sciences
University of Canterbury
Private Bag 4800
Christchurch, New Zealand

*Present address: Department of Earth Sciences, Monash University, Clayton 3168, Australia.

Abstract  The 0.23 Ma Kaingaroa Ignimbrite represents the only large-scale eruption from Reporoa Caldera, Taupo Volcanic Zone, New Zealand. A combination of detailed volcanology and lithic componentry of the Kaingaroa Ignimbrite and morphological and geophysical data on the caldera has constrained the development of Reporoa Caldera.

The Kaingaroa Ignimbrite eruption evolved from a single vent during the initial stages of the eruption, to a trapdoor caldera with the opening up of fractures coincidental with regional faults along the eastern margin, from which the main part of the Kaingaroa Ignimbrite was erupted. Finally, caldera collapse occurred during the later stages of the eruption. Asymmetric ignimbrite and facies distribution is interpreted as largely resulting from eastward-directed pyroclastic flows erupted during intially asymmetric caldera subsidence.

Keywords  caldera; lithic fragments; Kaingaroa Ignimbrite; Taupo Volcanic Zone; vent evolution

New Zealand Journal of Geology & Geophysics, 2000, Vol. 43: 471-481

0028-8306/00/4303-0471 $7.00/0 (c) The Royal Society of New Zealand 2000

PDF file of entire paper: medium quality (2294K); (scanned from paper original: notes about this process)

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