... horizontal stress through rifting-related processes would cause mild overpressure and drive magma sideways, rather than to the surface ( Lister, 1990 ). The area northeast of Taupo is intensively faulted, and the Kaiapo fault ( Fig. 1 ) was a clean scarp against which Oruanui ignimbrite was banked in later...

... pyroclastic deposits. ( A ) Typical proximal plinian fall deposit (Oruanui, New Zealand). Note the uniformity of particle sizes, the particle angularity and the absence of fine-ash matrix, the result of winnowing in the high eruption plume. Darker fragments are lithic material. ( B ) Typical ignimbrite...

... OI, Oruanui ignimbrite P1, Paleosol 1 P2, Paleosol 2 PID, proportional-integral-derivative TI, Taupo ignimbrite TDR, time domain reflectometry The design, installation, and evaluation of a vadose zone flux monitoring system is described. This system has 15 automated equilibrium...

...Figure 2. A, B: Relative abundances of diatom species groups in lithic clasts extracted from proximal Oruanui (New Zealand) ignimbrite (A) and Oruanui fallout tephra (B), shown with increasing distance from source. Six species groups: i— Aulacoseira ambigua ; ii— Cyclostephanos novaezeelandiae...

... supereruptions that show field evidence for contrasting behavior at eruption onset: (1) 650 km 3 , 0.767 Ma Bishop Tuff, Long Valley; (2) 530 km 3 , 25.4 ka Oruanui eruption, Taupo; and (3) 2500 km 3 , 2.08 Ma Huckleberry Ridge Tuff, Yellowstone. During magma ascent, decompression causes volatile exsolution from...

... of volcanoclastic rocks of the Huka Falls Formation ( Chambefort et al., 2014 ), overlain by the Oruanui Formation ignimbrite ( Wilson, 2001 ; Manville and Wilson, 2004 ), a layer of loess and gravels ( Vucetich and Pullar, 1969 ), and ignimbrite from the CE 232 Taupo volcanic eruption ( Wilson, 1985 ; Hogg et al...

... ka Taupo ignimbrite formed during the climax of eruption Y ( Cole et al. 1998; J.W. Cole & R.M. Burt pers. comm. 1997), suggesting that the post‐Oruanui eruptions may have constructed a dome complex in the eastern part of Lake Taupo. Repose periods vary by more than two orders of magnitude from...

..., at 515 m ASL. This contrasts strongly with modern deformation rates, which, if extrapolated over 26 500 years, would place the post-26.5 ka shoreline close to modern lake level ( Fig. 3 ). Displacements on most Taupo Fault Belt faults immediately north of Lake Taupo offset the Oruanui ignimbrite surface...

...FIGURE 3 Feldspar from the Oruanui Ignimbrite, Taupo, New Zealand, showing isotopic variation from core to rim. The ignimbrite is 26,500 years old; so, given the low Rb/Sr of the feldspar, the ratios measured are initial ratios with no age correction necessary [analytical precision is about ±30...

... to the low proportion of radiogenic Pb. Nine grains contain <20% common Pb and yield ages of 0.21 ± 0.03 to 0.74 ± 0.06 Ma (uncertainties are 2σ). Most of the 23 listed Quaternary grains have ages similar to those from the 340 ka Whakamaru ignimbrite ( Fig. 3 ), erupted from a large caldera overlapping...

... diffusion profiles. We investigate three large-volume, high-silica rhyolite eruptions: the 240 ka Ohakuri-Mamaku and 26.5 ka Oruanui (Taupo Volcanic Zone, New Zealand), and the 760 ka Bishop Tuff (California, USA). Our results show that (1) longevity estimates from melt inclusion textures and Ti diffusion...