Table 2.

Average major element and volatile composition of melt inclusions for the analysed eruptive units

SiO2 (wt%)TiO2 (wt%)Al2O3 (wt%)FeO (wt%)MnO (wt%)MgO (wt%)CaO (wt%)Na2O (wt%)K2O (wt%)P2O5 (wt%)H2O (wt%)H2O (wt%)CO2 (ppm)Cl (wt%)F (wt%)
Kaharoa (n=64)
Taupo (n=26)
 avg. (n=4)76.600.2413.351.760.080.221.363.552.810.03nanana
 avg.* (n=22)74.850.4013.692.540.120.371.523.552.880.07nanana0.240.04
Oruanui (n=25)
Rotoiti (n=25)
Mamaku (n=73)
 Type 1 – avg.78.370.1311.940.990.040.050.533.804.
 Type 2 – avg.78.610.1311.791.
Ohakuri (n=97)
 Fall deposit – avg.77.990.0812.150.950.050.060.554.
 Type 1 – avg.78.560.0911.761.
 Type 2 – avg.78.890.1111.621.
 Type 3 – avg.79.470.1411.370.960.030.050.543.873.610.01na4.02na
Kaingaroa (n=22)*
Matahina (n=36)
  • Analyses are normalized to anhydrous conditions (na – not analysed). Major elements for the Mamaku and Ohakuri eruptive deposits are after Bégué et al. (2014). Major elements and Cl and F analysed by electron microprobe (EMPA) at the University of Washington and Oregon State University. Analytical conditions for major elements: acceleration voltage 15 kV, beam current 5 nA, beam size 10 µm. Cl and F analysed using a beam blanking technique (Witter & Kuehner 2004) with an acceleration voltage of 10 kV, beam current of 100 nA and beam size 10 µm, and with standard analytical conditions at Oregon State University. Analytical error for Cl is <3% and c. 10% for F.

  • *Plagioclase-hosted melt inclusions.

  • Transmission FTIR.

  • Reflectance FTIR.

  • For CO2 and H2O analyses (analysed at Oregon State University): uncertainties in measuring inclusion thickness and fitting the background are typically, 0.3 wt% for H2O and, 5% for CO2 using the transmission FTIR; estimated error on H2O using the reflectance FTIR is +0.5 wt%.