Quaternary acid magma in New Zealand

@article{Ewart1975QuaternaryAM,
  title={Quaternary acid magma in New Zealand},
  author={Anthony Ewart and Wes Hildreth and Ian Carmichael},
  journal={Contributions to Mineralogy and Petrology},
  year={1975},
  volume={51},
  pages={1-27}
}
AbstractThe voluminous Pleistocene—Recent Taupo rhyolites typically contain phenocrysts of plagioclase (oligoclase-labradorite), quartz, titanomagnetite, ilmenite, and ferromagnesian silicates. Ferromagnesian assemblages correlate with well defined Fe-Ti oxide equilibration temperature ranges and allow the rhyolites to be subdivided as follows: (1) Cummingtonite (c)—calcic hornblende (hb)—orthopyroxene (opx); 725–755°C, (2) Hb-opx, 750–825°C, (3) Biotite-hb-(c-opx), 720–765°C, (4) Opx… 

The 26·5 ka Oruanui Eruption, Taupo Volcano, New Zealand: Development, Characteristics and Evacuation of a Large Rhyolitic Magma Body

The caldera-forming 26•5 ka Oruanui eruption (Taupo, New Zealand) erupted ~530 km3 of magma, >99% rhyolitic, <1% mafic. The rhyolite varies from 71•8 to 76•7 wt % SiO2 and 76 to 112 ppm Rb but is

The volatile component of quaternary ignimbrite magmas from the North Island, New Zealand

AbstractIgnimbrites from the central North Island consist mainly of glass or its devitrified product (70–95%); their phenocryst mineralogy is varied and includes plag., hyp., ti-mag., ilm., aug.,

Correlation of rhyolitic pyroclastic eruptive units from the Taupo volcanic zone by Fe–Ti oxide compositional data

Abstract Grain-specific analyses of Fe–Ti oxides and estimates of eruption temperature (T) and oxygen fugacity (fO2) have been used to fingerprint rhyolitic fall and flow deposits that are important

Reactivation of a rhyolitic magma body by new rhyolitic intrusion before the 15.8 ka Rotorua eruptive episode: implications for magma storage in the Okataina Volcanic Centre, New Zealand

The 15.8 ka Rotorua rhyolite eruptive episode from the Okataina Volcanic Centre comprises a plinian pumice fall deposit followed by the extrusion of two rhyolitic lava domes or flows and their

The petrogenesis of an I-type volcanic-plutonic suite: The St. Marys Porphyrite, Tasmania

The Devonian I-type St. Marys Porphyrite (388±1Ma) comprises two petrographically similar units, an 800 m thick pyroclastic sheet (compositionally dacite and rhyolite) and a subvolcanic feeder dyke.

Reactivation of a rhyolitic magma body by new rhyolitic intrusion before the 15 . 8 ka Rotorua eruptive episode : implications for magma storage in the Okataina Volcanic Centre , New Zealand

The 15.8 ka Rotorua rhyolite eruptive episode from the Okataina Volcanic Centre comprises a plinian pumice fall deposit followed by the extrusion of two rhyolitic lava domes or flows and their

Status of thermobarometry in granitic batholiths

  • J. Anderson
  • Geology
    Earth and Environmental Science Transactions of the Royal Society of Edinburgh
  • 1996
ABSTRACT: Most granitic batholiths contain plutons which are composed of low-variance mineral assemblages amenable to quantification of the P– conditions that characterise emplacement. Some mineral

Mineralogy and geothermometry of high-temperature rhyolites from the central and western Snake River Plain

Voluminous mid-Miocene rhyolitic ash-flow tuffs and lava flows are exposed along the northern and southern margins of the central and western Snake River Plain. These rhyolites are essentially
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