Volatile Solubility Degassing Fraction

Solve single-volatile closed-system exsolution conserving nonvolatile melt while saturation is defined on residual melt mass; not a naive initial-fraction difference or a pressure-solubility reference table.

Description

Volatile exsolution transfers dissolved gas from melt into a separate phase.

Volatile exsolution transfers dissolved gas from melt into a separate phase. Its fraction must account for the shrinking residual melt mass.

When to use Volatile Solubility Degassing Fraction

Use this tool to solve single-volatile closed-system exsolution conserving nonvolatile melt while saturation is defined on residual melt mass; not a naive initial-fraction difference or a pressure-solubility reference table.

Gather the relevant observations and fitted model parameters. Use the stated units and time basis; keep paired observations aligned.

How to use Volatile Solubility Degassing Fraction and understand its results

Gather the relevant observations and fitted model parameters. Use the stated units and time basis; keep paired observations aligned.
Enter initialVolatileMassFraction, initialMagmaMassKg, dissolvedVolatileCapacityFractionInResidualMelt using the field table and calculation rules, then run the tool.
Read exsolvedVolatileMassKg, dissolvedVolatileMassKg, exsolvedFractionOfInitialVolatile. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
initialVolatileMassFraction	Initial volatile mass fraction	number	Required
initialMagmaMassKg	Initial magma mass kg	number	Required
dissolvedVolatileCapacityFractionInResidualMelt	Dissolved volatile capacity fraction in residual melt	number	Required

Supply positive magma mass, an initial volatile fraction strictly between zero and one, and residual capacity from zero through that initial fraction. Subtract exsolved mass from initial volatile mass and divide by the initial volatile mass to obtain the exsolved share.^[1]

exsolved mass = M(initial fraction − residual capacity)/(1 − residual capacity)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
exsolvedVolatileMassKg	Exsolved volatile mass kg	number
dissolvedVolatileMassKg	Dissolved volatile mass kg	number
exsolvedFractionOfInitialVolatile	Exsolved fraction of initial volatile	number

json

{
  "input": {
    "initialVolatileMassFraction": 0.1,
    "initialMagmaMassKg": 100,
    "dissolvedVolatileCapacityFractionInResidualMelt": 0.05
  },
  "output": {
    "exsolvedVolatileMassKg": 5.2631578947368425,
    "dissolvedVolatileMassKg": 4.7368421052631575,
    "exsolvedFractionOfInitialVolatile": 0.5263157894736843
  }
}

Limitations and assumptions

Single-volatile closed-system mass balance; pressure-dependent solubility and open-system gas loss are not solved.

Numbers and computed results must be finite; overflow produces an error. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Bubble Nucleation Supersaturation Drop: Screen Laplace critical radius after a caller decompression while gas-equivalent pressure remains fixed; homogeneous nucleation barriers/kinetics and eruption triggering are not established. For a complementary task, use CO2 SO2 Molar Ratio Volcanic: Convert paired mass concentrations to a blank-corrected volcanic CO2/SO2 molar ratio on the same gas basis; signed CO2 nondetections remain explicit and a nonpositive SO2 denominator is not assigned a ratio.

References

Volatile Solubility Degassing Fraction — tool.io

Similar or alternative tools

Bubble Nucleation Supersaturation Drop
Screen Laplace critical radius after a caller decompression while gas-equivalent pressure remains fixed; homogeneous nucleation barriers/kinetics and eruption triggering are not established.
CO2 SO2 Molar Ratio Volcanic
Convert paired mass concentrations to a blank-corrected volcanic CO2/SO2 molar ratio on the same gas basis; signed CO2 nondetections remain explicit and a nonpositive SO2 denominator is not assigned a ratio.