The central Taupo Volcanic Zone is a region of intense
Quaternary silicic volcanism accompanying rapid crustal extension. Modem central
TVZ is the most frequently active and productive silicic volcanic system on
Earth, erupting rhyolite at c.0.28 m3 s-1.
The rhyolites show no major compositional changes with time, but the total
extent of magma chamber zonation has changed with the advent of rifting and
crustal extension at c.0.7 Ma. At least 34 caldera-forming ignimbrite eruptions
have formed a complex sequence of relatively short-lived, nested and/or
overlapping volcanic centres in central TVZ. Taupo contrasts with other large
silicic magmatic systems in the exceptionally high frequency, but small size, of
caldera forming eruptions. This contrast reflects the thin, rifted nature of the
TVZ crust that precludes the development of long term magmatic cycles at Taupo.
Within central TVZ, non-rhyolitic compositions have been erupted apparently
irregularly in time and space; in particular there is no evidence for a
geographic separation of basalts from andesites. TVZ is a rifted arc, but its
segmented nature, high thermal flux and voluminous rhyolitic volcanism make it
unique on Earth.