Geothermal activities in the Main Ethiopian Rift: Hydrogeochemical characterization of geothermal waters and geothermometry applications (Dofan-Fantale, Gergede-Sodere, Aluto-Langano)

Pürschel, M.; Gloaguen, Richard; Stadler, Susanne

doi:10.1016/j.geothermics.2013.01.001

Cited by 38 publications

(27 citation statements)

References 29 publications

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“…Most studies do not systematically record spring geochemistry, and further work is recommended. Hot springs vary in temperature with values commonly around 40–60°C, higher temperatures reach 80–100°C (e.g., 81.5°C, Habilo; Bekele et al, ; 82°C, Langano; Pürschel et al, ; 95°C, Chokore; UNDP, ).…”

Section: Resultsmentioning

confidence: 99%

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Spatially Variable CO₂ Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions

Hunt

Zafu

Mather

et al. 2017

Geochem Geophys Geosyst

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Deep carbon emissions from historically inactive volcanoes, hydrothermal, and tectonic structures are among the greatest unknowns in the long‐term (∼Myr) carbon cycle. Recent estimates of diffuse CO2 flux from the Eastern Rift of the East African Rift System (EARS) suggest this could equal emissions from the entire mid‐ocean ridge system. We report new CO2 surveys from the Main Ethiopian Rift (MER, northernmost EARS), and reassess the rift‐related CO2 flux. Since degassing in the MER is concentrated in discrete areas of volcanic and off‐edifice activity, characterization of such areas is important for extrapolation to a rift‐scale budget. Locations of hot springs and fumaroles along the rift show numerous geothermal areas away from volcanic edifices. With these new data, we estimate total CO2 emissions from the central and northern MER as 0.52–4.36 Mt yr−1. Our extrapolated flux from the Eastern Rift is 3.9–32.7 Mt yr−1 CO2, overlapping with lower end of the range presented in recent estimates. By scaling, we suggest that 6–18 Mt yr−1 CO2 flux can be accounted for by magmatic extension, which implies an important role for volatile‐enriched lithosphere, crustal assimilation, and/or additional magmatic intrusion to account for the upper range of flux estimates. Our results also have implications for the nature of volcanism in the MER. Many geothermal areas are found >10 km from the nearest volcanic center, suggesting ongoing hazards associated with regional volcanism.

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Section: Resultsmentioning

confidence: 99%

“…Measurement points, filled circles; known hot spring and fumarole locations, red arrows and diamonds respectively. Sources : Braddock et al (), MOWR (), Geological Survey of Ethiopia and United Nations (), and Pürschel et al (); see supporting information Tables 1 and 2.…”

Section: Methodsmentioning

confidence: 99%

Spatially Variable CO₂ Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions

Hunt

Zafu

Mather

et al. 2017

Geochem Geophys Geosyst

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“…The Na-K-Mg 1/2 triangular diagram 43 provides an indication of the suitability of the waters for the application of solute geothermometers. 44 This diagram ( Figure 5) shows that most samples (W 1 ,W 2 ,S P ,W 3 ,W 4 ) plot in the immature waters field indicating the interaction water-rock along the flow path and that water did not reach ionic equilibrium. The TS 1 ,TS 2 &TS 1 -R samples present more suitability for geothermometry estimates and plot in the partially equilibrated field yielding temperatures between 80°C and 100°C.…”

Section: Geothermometrymentioning

confidence: 99%

Investigating regional groundwater flow systems in baja california central desert region

Ouysse¹,

Wehncke²,

Rivera³

2018

IJH

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In Northern Baja California, environmental conservation may not be fully accomplished in the absence of a clear understanding of key factors controlling and protecting biodiversity. Groundwater is an environmental agent triggering the presence of a wide range of arid ecosystems; therefore, any sustainable development in the region has to maintain a balance between environmental, social and economical benefits. The present study has placed a great emphasis on the understanding and distribution of groundwater flow systems, and their environmental interactions in the protected area of the Valle de Los Círios, using physical-chemical and isotope methods. Results show the presence of three groundwater groups portraying contrasting flow systems conditions. Analyzed samples have been classified as fresh-brackish, and thermal alkaline groundwater as suggested by pH, temperature and TDS. The Br/Cl ratio in most samples was close to the ocean molar value (1.5x10 -3 ) indicating the importance of marine aerosol fraction in the recharged waters; however, Mg/Cl,Na/Cl,Ca/Cl,SO 4 / Cl and Cl/HCO 3 +Cl ratios were significantly different to those of seawater mixing conditions. Dominant ions (Na,Ca and Cl), chemical age proxies (Li), and δ 18 O suggest waters with long residence time, with the possibility of been recharge during the late glacial period. Thermal ground water shows low minor and trace element content and exhibits the dominance of Na-plagioclase hydrolysis; their low levels of Sr and Ba suggest negligible contact with calcareous rocks and their estimated temperature at depth (80to100°C) and TDS suggest groundwater has travelled through fractured media. This introduction study suggests that desertic species in Valle de Los Cirios are highly sustained by groundwater of local and intermediate flows.

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“…Besides Aluto, knowledge of the geothermal potential of other areas in Ethiopia has increased in recent years; examples include i) Tendaho in the Afar depression (Didana et al, 2015), ii) Gedemsa-Sodere and iii) Corbetti (Teklemarian and Kebede, 2010;Kebede, 2014); these latter two are located within the MER. Apart from these areas, there are several other promising places along the MER that are still in a preliminary exploration phase (Purschel et al, 2013).…”

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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Geothermal activities in the Main Ethiopian Rift: Hydrogeochemical characterization of geothermal waters and geothermometry applications (Dofan-Fantale, Gergede-Sodere, Aluto-Langano)

Cited by 38 publications

References 29 publications

Spatially Variable CO₂ Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions

Spatially Variable CO₂ Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions

Investigating regional groundwater flow systems in baja california central desert region

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

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Geothermal activities in the Main Ethiopian Rift: Hydrogeochemical characterization of geothermal waters and geothermometry applications (Dofan-Fantale, Gergede-Sodere, Aluto-Langano)

Cited by 38 publications

References 29 publications

Spatially Variable CO2 Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions

Spatially Variable CO2 Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions

Investigating regional groundwater flow systems in baja california central desert region

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

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Product

Resources

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Spatially Variable CO₂ Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions

Spatially Variable CO₂ Degassing in the Main Ethiopian Rift: Implications for Magma Storage, Volatile Transport, and Rift‐Related Emissions