Soil Gas Sampling
Exploration Technique: Soil Gas Sampling
|Exploration Technique Information|
|Exploration Group:||Field Techniques|
|Exploration Sub Group:||Field Sampling|
|Parent Exploration Technique:||Gas Sampling|
|Information Provided by Technique|
|Stratigraphic/Structural:||Identify concealed faults that act as conduits for hydrothermal fluids.|
|Hydrological:||Identify hydrothermal gases of magmatic origin.|
|Thermal:||Differentiate between amagmatic or magmatic sources heat.|
Soil gas sampling techniques are also used in ongoing measurement of the gas contents of soils in volcanic hazard monitoring. For example, gas flux and soil gas sampling techniques have been used to monitor potentially deadly CO2 emissions at the Long Valley Caldera, CA since the early 90s, when a period of intense seismic activity associated with dike intrusion and/or magmatic fluid migration caused an increase in CO2 flux to the surface, resulting in localized tree kills around Horseshoe Lake at the base of Mammoth Mountain.
Exact field procedures may vary depending on the vapor sampling apparatus used. For detailed information on sampling methods and analysis of soil gas samples and their use in evaluating geothermal resources in different environments, consult Lechler et al. (2009), Voltattorni et al. (2010), Klingel et al. (2011).
Analysis and comparison of hydrothermal gas concentrations in soil gas samples can be used to:
- Presence or absence of hydrothermal gases of magmatic origin.
- Differentiate between amagmatic or magmatic sources of soil gases.
- Temperature estimates of the geothermal source reservoir based on multiple gas geothermometers.
- Determine geometry and/or location of the geothermal source.
- Estimate relative depth to an inferred magmatic source.
- Identify concealed faults that act as conduits for hydrothermal fluids.
- Estimate relative fracture effective porosity versus porous medium effective porosity.
- Assist in siting locations for exploratory slim holes and surface geophysical surveys.
- Toxic Substances Hydrology Program
- The Application of Soil-Gas Technique to Geothermal Exploration: Study of Hidden Potential Geothermal Systems
- Near-Surface CO2 Monitoring And Analysis To Detect Hidden Geothermal Systems
- J.L. Lewicki, M.L. Fischer, G.E. Hilley. 2008. Six-Week Time Series Of Eddy Covariance CO2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing. Journal of Volcanology and Geothermal Research. 171(3-4):178-190.
- Multi-Gas Geochemistry at the Desert Queen Geothermal System, West-Central Nevada
- Shallow Hydrothermal Gas Sampling and Analysis as an Exploration Tool for Magmatic Geothermal Sources
|Page||Area||Activity Start Date||Activity End Date||Reference Material|
|Soil Gas Sampling At Chena Geothermal Area (Kolker, 2008)||Chena Geothermal Area||1979||1980||
|Soil Gas Sampling At Kilauea East Rift Geothermal Area (Cox, 1980)||Kilauea East Rift Geothermal Area||1978||1978|