Fig. 3: The gas composition of fluid inclusions is modeled as a mixture between modern atmospheric air and air-saturated water (modified from Park & Schaller (2025)61).
From: Fluid inclusions: tiny windows into global paleo-environments
The resulting composition depends on the relative contribution of each endmember, governed by the gas volume fraction (φg). When φg = 1, the inclusion reflects the atmospheric composition, when φg = 0, it reflects the composition of dissolved gases in water. Theoretical trapped mole fractions of N2, O2, Ar, and CO2 are shown on (a), with the wide range of possible CO2 mole fractions shown altogether with Ar on a logarithmic y-axis. Ranges of selected elemental ratios are shown on (b). All calculations using solid lines assume 20 °C freshwater, whereas dotted lines show calculations for 90 °C seawater, for comparison.
