Research ArticleGEOLOGY

Quantifying gas emissions from the “Millennium Eruption” of Paektu volcano, Democratic People’s Republic of Korea/China

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Science Advances  30 Nov 2016:
Vol. 2, no. 11, e1600913
DOI: 10.1126/sciadv.1600913
  • Fig. 1 Map showing the location of Paektu volcano and associated tephra fallout and gas yields from large historic eruptions.

    (A) Map showing the location of Paektu volcano (black triangle) and isopachs illustrating the extensive dispersal of tephra fallout from the ME [data from Machida et al. (61)]. Numbers within each oval indicate the thickness of tephra. Base map data from MapBox and OpenStreetMap. (B) Total S and halogen (F + Cl) yields from large historic eruptions, with eruption dates given in parentheses. Taupo, Katmai, Krakatau, and Tambora S yields from ice core (IC) (58). Pinatubo S yield from satellite remote sensing (RS) (72). Laki S and halogen yields estimated by the petrologic method over a period of 8 months (P) (73). Soufriere Hills and Mt. St. Helens (MSH) gas yields by the petrologic method (P) (74). The estimates for the Paektu ME are from this work (red bars) or by the petrologic method (blue bars) (20). Numbers above red bars indicate change in halogen and S yields estimated by this work compared to the estimates of Horn and Schmincke (20).

  • Fig. 2 Incompatible element (U) versus volatile plots illustrating trends in Paektu MI chemistry.

    An increase in U concentration represents continued crystallization-evolution of the magma. The “Fluid absent crystallization” line represents the expected trend for MI chemistry in a fluid-absent system, where volatile and incompatible elements will be equally enriched in the melt as crystallization progresses. The red lines (in essence, the difference between the expected and actual average comendite MI volatile concentration) represent the amount of that volatile exsolved as a separate fluid (bubble) phase. The orange dashed lines (in essence, the difference between average comendite MI and MG concentrations) represent the amount of that volatile degassed during decompression and ascent upon eruption. Error bars are calculated on the basis of relative errors reported in table S2.

  • Fig. 3 Isothermal P-X projection showing the compositions of coexisting vapor and liquid brine phases in the H2O-NaCl system after the study by Bodnar et al. (38).

    The solvus that exists at multiple temperatures below ca. 2000 bars indicates the composition of both Cl-poor vapor (left of the critical curve) and Cl-rich liquid brine (right of the critical curve), which coexist as immiscible fluids at magmatic pressures and temperatures. The yellow star indicates the NaCl content of pre-eruptive ME fluid at P and T inferred for comenditic ME melt inclusions, and the blue bar indicates the range in the NaCl content of the vapor given the range in P calculated on the basis of MI H2O contents.

  • Fig. 4 Breakdown of fluid source and composition.

    This diagram illustrates the proportional contribution and composition of both pre- and syn-eruptive fluid, plus the total gas yield, which is equal to the sum of the two fluid types. Colored circles represent each fluid species (H2O, S, F, Cl, and CO2), and the area of the circles corresponds to the fluid mass in teragrams (see figure legend). Gray bars illustrate the proportional contribution of each fluid type (pre- and syn-eruptive) to the total yield and correspond to the vertical axis.

  • Fig. 5 Schematic drawing of the ME magma chamber beneath Paektu before eruption.

    An upper chamber of crystal-poor comendite magma is generated by crystal settling and/or filter pressing of a crystallizing comendite magma (50, 51, 75). Crystals settle out of the main chamber and condense into mush (~50% crystals) and outer rigid sponge (>65% crystals) zones (47). Parental trachyte feeder dikes supply the comendite chamber with new magma, promoting prolonged crystallization-driven gas exsolution within the chamber. Exsolution of volatile-bearing melt during ascent further propels the magma upward and, along with pre-eruptive gas, results in a ca. 25-km-high Plinian eruption column and extensive tephra fallout. S (45 Tg) and halogens (78 Tg) are released, and much of this gas is likely injected into the upper atmosphere.

  • Table 1 Volatile concentrations in MI and MG, expected fluid-absent concentrations in evolved MI, and Δvolatile values for pre- and syn-eruptive fluids.

    U concentration is used as an index of differentiation. All analyses are in parts per million, unless noted. Numbers in parentheses represent 1σ uncertainty in units of the last reported digits. H2O and CO2 are measured by transmission or ATR FTIR. S, F, and U are measured by SHRIMP. Cl is measured by EMP. n, number of MI averaged.

    Trachyte MI average
    concentration
    nComendite MI
    average
    concentration
    nMG
    average
    concentration
    Expected
    fluid-absent
    concentration
    ΔVolatile
    (pre-eruptive)
    ΔVolatile
    (syn-eruptive)
    H2O wt %1.72 (24)132.40 (23)370.3 (15)6.183.782.10
    S197 (5)35110 (3)5359 (1)90579551
    F917 (28)353354 (104)533128 (97)4220896226
    Cl987 (53)413974 (215)734166 (225)45300
    CO223 (2.6)*90
    U2.3 (1)4110.7 (7)7310 (6)

    *Measured in rehomogenized bubble-bearing MI (see Materials and Methods).

    • Table 2 Pre- and syn-eruptive and total gas compositions and masses.
      Tg
      (pre-eruptive)
      wt %
      (pre-eruptive)
      Tg
      (syn-eruptive)
      wt %
      (syn-eruptive)
      Tg
      (total yield)
      wt %
      (total yield)
      H2O2006 (775)84.11115 (623)98.63121 (1154)88.7
      S42 (9)1.83 (0.6)0.245 (10)1.3
      F46 (10)1.912 (2.6)1.158 (13)1.6
      Cl20 (9)0.80020 (9)0.6
      CO2272 (123)11.41 (0.3)0.1273 (111)7.8
      Total2386 (1036)1131 (773)3517 (1807)

      Numbers in parentheses represent propagated uncertainties in units of the last reported digits. See the Supplementary Materials for details of the calculation of uncertainties.

      Supplementary Materials

      • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/11/e1600913/DC1

        table S1. Whole-rock pumice compositions by XRF, microprobe, and FTIR.

        table S2. Major, trace, and volatile element analyses in ME MIs.

        table S3. Compositions of phases used in least squares linear regression modeling.

        table S4. Results of least squares linear regression modeling of the derivation of PEK-62 comendite from CBS-TPUM trachyte.

        table S5. H2O contents in comenditic MI and modeled saturation pressures.

        table S6. Excel file listing raw FTIR data, all values necessary for calculation of H2O and CO2 concentrations from FTIR data, and associated errors of measured and calculated values.

        table S7. Excel file listing all values used to calculate volatile fluxes and associated errors.

      • Supplementary Materials

        This PDF file includes:

        • table S1. Whole-rock pumice compositions by XRF, microprobe, and FTIR.
        • table S2. Major, trace, and volatile element analyses in ME MIs.
        • table S3. Compositions of phases used in least squares linear regression modeling.
        • table S4. Results of least squares linear regression modeling of the derivation of PEK-62 comendite from CBS-TPUM trachyte.
        • table S5. H2O contents in comenditic MI and modeled saturation pressures.

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        Other Supplementary Material for this manuscript includes the following:

        • table S6. Excel file listing raw FTIR data, all values necessary for calculation of H2O and CO2 concentrations from FTIR data, and associated errors of measured and calculated values.
        • table S7. Excel file listing all values used to calculate volatile fluxes and associated errors.

        Files in this Data Supplement: