Two phase (l-v) steady state diffusion of water isotopes: A Rayleigh approximation and aTwo phase (l-v) steady state diffusion of water isotopes: A Rayleigh approximation and applicationpplication

Primary Author: Anthony Sorensen

Faculty Sponsor: Peter Larson


Primary College/Unit: Arts and Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman




Principal Topic

Hydrothermal (geothermal) systems are defined by water isotope concentrations and other various geochemical characteristics.  The defining characteristics of a hydrothermal system are volumetrically dependent on the subsurface reservoir. If the volume of H2O is the primary control of water isotopes and hydrothermal system characteristics, then the isotopic evolution of a hot spring fluid is best modeled by the two phase (liquid-vapor) steady state diffusion equation. Volumetric ratios of liquid to vapor (l-v) within the reservoir can be used as an indicator of lifetime remaining in the hydrothermal system and thus can be used to make approximations about the next Yellowstone eruption.


The boiling experiment acted as an analog of a steady state hydrothermal system.  The two-phase steady state diffusion equation was used to model the isotopic evolution of the water isotopes. In this experiment, water isotope analyses were continuously measured using a mass spectrometer, and the results were normalized to the fraction of liquid remaining in the system.


The models developed from this study have unique applications that include: (a) providing percentage estimates of the liquid reservoir remaining in hydrothermal (geothermal) areas (i.e. time remaining before the next eruption, in Yellowstone) and (b) providing a time constraint (i.e. a rate limiting step) in more complex geochemical modeling. Additionally, understanding the volume of H2O remaining in geothermal systems has the potential to save energy companies enormous sums of money by decreasing the amount of drilling needed in geothermal energy development.