Redox control of gas compositions in Philippine volcanic-hydrothermal systems
| Autor: | Werner F. Giggenbach |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
geography
geography.geographical_feature_category Renewable Energy Sustainability and the Environment Chemistry Front (oceanography) Mineralogy Geology Geotechnical Engineering and Engineering Geology Redox Hydrothermal circulation Methane chemistry.chemical_compound Volcano Carbon dioxide Sulfate minerals Chemical composition |
| Zdroj: | Geothermics. 22:575-587 |
| ISSN: | 0375-6505 |
| DOI: | 10.1016/0375-6505(93)90037-n |
| Popis: | Gas samples from five volcanic-hydrothermal systems in the Philippines were analysed for CO2, H2S, NH3, H2, He, Ne, Ar, N2, CH4 and CO. Even in systems with sulfate minerals as common components of alteration assemblages, indicating highly immature, oxidising conditions at depth, the redox potential governing the concentrations of the reactive gases CO2, H2S, H2, CH4 and CO approaches closely that expected for attainment of equilibrium with rock in more mature, reduced systems. The finding suggests that overall fluid compositions reflect more closely redox conditions established at the advancing front of interaction with primary rock rather than those of equilibrium with the set of secondary minerals left behind. With the exception of CO and NH3, the close agreement in the compositions of gas samples, taken from pools and deep wells indicates that secondary processes have only a slight effect on the vapors during their rise from drilled depths (1.8 km) to the surface and that samples from natural features may be taken to be representative of redox conditions at drilled depths. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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