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Fig. 6 | Earth, Planets and Space

Fig. 6

From: Petrological characteristics and volatile content of magma of the 1979, 1989, and 2014 eruptions of Nakadake, Aso volcano, Japan

Fig. 6

Volatile content of melt inclusions and glass in the groundmass in the scoria. The CO2/H2O, CO2/SO2, and H2O/SO2 ratios of the volcanic gases are shown as solid lines (type A) and dashed lines (type B). a H2O and CO2 content of the melt inclusions analyzed by SIMS. H2O and CO2 contents of the melt of the A1, A2, A3, B1, B2, and B3 magmas calculated by MELTS at 1079 °C (Table 5; Additional file 3: Table S2) are also shown. b S and CO2 contents of the melt inclusions. c H2O and S contents of the melt inclusions. d Cl and S contents of the melt inclusions. e Possible evolution processes of H2O and CO2 in a magma chamber for (I) fractional crystallization of gas-undersaturated magma, (II) isobaric fractional crystallization of gas-saturated magma, (III) degassing with pressure decrease, and (IV) addition of CO2-rich bubbles to gas-saturated magma (Saito et al. 2001). Process (III) causes an initial drastic decrease in CO2 concentration (as shown by “Early”), which is followed by a decrease in H2O concentration (as shown by “Late”) because of the lower solubility of CO2 compared with H2O. The symbols are the same as in Fig. 5. Error bars indicate the analytical errors of H2O and CO2 by SIMS and those of S and Cl by EPMA. The analytical error of H2O by EPMA in (c) is ± 1 wt%

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