New Zealand Journal of Geology and Geophysics abstracts
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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