Chemical geothermometers and mixing models for geothermal systems

Fournier, Robert O.

doi:10.1016/0375-6505(77)90007-4

Cited by 755 publications

(408 citation statements)

References 11 publications

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“…The dependences on temperature of the solubility of chalcedony (Arnorsson, 1983) and quartz (Fournier, 1977) where SiO 2 is in mg/L. At temperatures b180°C, such as those estimated by both Eqs.…”

Section: Geothermometrymentioning

confidence: 99%

Fluid geochemistry of a deep-seated geothermal resource in the Puna plateau (Jujuy Province, Argentina)

Arnold

Cabassi

Tassi

et al. 2017

Journal of Volcanology and Geothermal Research

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This study focused on the geochemical and isotopic features of thermal fluids discharged from five zones located in the high altitude Puna plateau (Jujuy Province between S 22°20′-23°20′ and W 66°-67°), i.e. Granada, Vilama, Pairique, Coranzulí and Olaroz. Partially mature waters with a Na + -Cl − composition were recognized in all the investigated zones, suggesting that a deep hydrothermal reservoir hosted within the Paleozoic crystalline basement represents the main hydrothermal fluid source. The hydrothermal reservoirs are mainly recharged by meteoric water, although based on the δ 18 O-H 2 O and δD-H 2 O values, some contribution of andesitic water cannot be completely ruled out. Regional S-oriented faulting systems, which generated a horst and graben tectonics, and NE-, NW-and WE-oriented transverse structures, likely act as preferentially uprising pathways for the deep-originated fluids, as also supported by the Rc/Ra values (up to 1.39) indicating the occurrence of significant amounts of mantle He (up to 16%). Carbon dioxide, the most abundant compound in the gas phase associated with the thermal waters, mostly originated from a crustal source, although the occurrence of CO 2 from a mantle source, contaminated by organic-rich material due to the subduction process, is also possible. Relatively small and cold Na + -HCO 3 − -type aquifers were produced by the interaction between meteoric water and Cretaceous, Palaeogene to Miocene sediments. Dissolution of evaporitic surficial deposits strongly affected the chemistry of the thermal springs in the peripheral zones of the study area. Geothermometry in the Na-K-Ca-Mg system suggested equilibrium temperatures up to 200°C for the deep aquifer, whereas lower temperatures (from 105 to 155°C) were inferred by applying the H 2 geothermometer, likely due to re-equilibrium processes during the thermal fluid uprising within relatively shallow Na-HCO 3 aquifers. The great depth of the geothermal resource (possibly N 5000 m b.g.l.) is likely preventing further studies aimed to evaluate possible exploitation, although the occurrence of Liand Ba-rich deposits associated may attract financial investments, giving a pulse for the development of this remote region.

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Section: Geothermometrymentioning

confidence: 99%

Fluid geochemistry of a deep-seated geothermal resource in the Puna plateau (Jujuy Province, Argentina)

Arnold

Cabassi

Tassi

et al. 2017

Journal of Volcanology and Geothermal Research

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“…One of the main reasons, consistent with incomplete geothermal evaluations in many other areas in the World, is because hot deep hydrothermal fluids only occasionally come in contact with shallow cold aquifer(s) along ascending convective branches in fault systems. The importance of this factor has been recognized for decades and is clearly demonstrated by common mixing processes occurring at various degrees between hot rising fluids and cold meteoric descending fluids (Fournier, 1977;Arnòrsson, 1985).…”

Section: Introductionmentioning

confidence: 99%

Geothermal potential and origin of natural thermal fluids in the northern Lake Abaya area, Main Ethiopian Rift, East Africa

Minissale

Corti

Tassi

et al. 2017

Journal of Volcanology and Geothermal Research

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In this study, the occurrence, chemical composition, origin and geothermal significance of thermal springs and fumaroles naturally discharging in the area located north of the Lake Abaya (western margin of the Main Ethiopian Rift, East Africa) are reviewed in relation with recent tectonics. All thermal springs showed a dominantly Na-HCO 3 composition, consistent with observations dating from at least 1972, and most of them displayed a narrow range of δD and δ 18 O isotopic compositions for water similar to regional meteoric origins. These observations suggest that water-rock interaction processes occur in all aquifers and dominate the contributions of water that actively circulate within thermal fluids, and also suggest a similar elevation of groundwater recharge throughout the study area. Most of the thermal springs are dominated by a CO 2 -rich gas phase and discharge along the active faults bordering the western edge of the Main Ethiopian Rift valley. The δ 13 C values of CO 2 and the 3 He/ 4 He isotopic ratios are consistent with the presence of mantle-derived fluids similar to what is observed in many other areas along the kinematically active African Rift, especially within Ethiopia. The application of geothermometric techniques in the liquid and the gas phases suggests the presence of a deep reservoir in which the fluids equilibrated at a maximum temperature of approximately 180°C. Additionally, the presence of fumaroles at boiling temperatures and water/mud boiling pools in several places suggests that the geothermal reservoir is positioned at a relatively shallow depth and likely located in the western side of the study area. The analysis of data collected throughout time reveals that the waters of Lake Abaya have experienced an increase in salinity of 20% paralleled contemporaneously with a decrease in pH and δ 18 O and δD of water in the last 40 years; these changes do not appear to be related to climate changeinduced increases in temperature or evaporation at the global scale.

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“…High ratios of sodium to potassium also imply elevated reservoir temperatures, but suggest that the waters equilibrated at temperatures not much higher than the measured temperatures (Mariner and Willey, 1976;White, 1970). Ratios of Na/K are strongly influenced by the amount of available calcium in the water and cannot be relied upon as geothermometers in waters, such as those at Klamath Falls, for which molal ratios of VCa/Na are greater than one and in dicated reservoir temperatures are low (Fournier andTruesdell, 1973, p. 1272).…”

Section: Relations Among Dissolved Constituentsmentioning

confidence: 90%

“…Although it is virtually certain that these are mixed waters, mixing models fail to provide reasonable estimates of reservoir 'Fournier andTruesdell, 1973, 1974. 'Mixing models based on auartz or chalcedony equilibria and a cold-water component having a silica concentration of 45 mg L~' and a temperature of 20°C (Truesdell and Fournier, 1977 (Fournier, 1977).…”

Section: Reservoir Temperatures Estimated From Chemical Geothermometersmentioning

confidence: 99%

Hydrogeologic appraisal of the Klamath Falls geothermal area, Oregon

Sammel¹

1980

Professional Paper

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Chemical geothermometers and mixing models for geothermal systems

Cited by 755 publications

References 11 publications

Fluid geochemistry of a deep-seated geothermal resource in the Puna plateau (Jujuy Province, Argentina)

Fluid geochemistry of a deep-seated geothermal resource in the Puna plateau (Jujuy Province, Argentina)

Geothermal potential and origin of natural thermal fluids in the northern Lake Abaya area, Main Ethiopian Rift, East Africa

Hydrogeologic appraisal of the Klamath Falls geothermal area, Oregon

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