Dry gas vents (“mazuku”) in Goma region (North-Kivu, Democratic Republic of Congo): Formation and risk assessment

Smets, B.; Tedesco, Dario; Kervyn, F.; Kies, A.; Vaselli, Orlando; Yalire, M.

doi:10.1016/j.jafrearsci.2010.04.008

Cited by 41 publications

(25 citation statements)

References 25 publications

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“…A number of caveats must be stated for using hot spring/geothermal feature locations as a proxy for geothermal activity, and by extension CO 2 emissions. Incidences of large CO 2 flux apart from associated geothermal features (cold, dry vents) have been reported in many regions globally, though not in the MER, e.g., Hokkaido, Japan (Hernández Perez et al, ), Lake Kivu, DRC (Smets et al, ), Mammouth Mountain, USA (Sorey et al, ), and Rungwe Volcanic Province, Southern Tanzania (Barry et al, ; de Moor et al, ). Hot springs are also intimately tied to local hydrology.…”

Section: Discussionmentioning

confidence: 99%

“…The extent to which CO 2 ‐rich fluids flow through faults is a key area of research, with implications for trapping and sealing CO 2 for storage (e.g., Dockrill & Shipton, ). In extreme cases, CO 2 leakage from the subsurface may result in the accumulation of lethal concentrations, presenting a hazard to life (Chiodini et al, ; Hernández Perez et al, ; Smets et al, ).…”

Section: Introductionmentioning

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: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

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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“…According to Google Earth Satellite imagery, this is a modern basalt complex hosting several calderas (e.g., Nyiragongo and Nyamulagira) and is associated with the western limb of the East African Rift. Proximity to Lake Kivu implies alteration at high water/rock ratios but SO 2 fumaroles and dry CO 2 , CH 4 , and hydrocarbon gas vents (“mazuku” or “evil winds”) are also present [ Smets et al ., ; Tedesco et al ., ]. This is a modern, equatorial volcanic complex implying that alteration occurred in a warm, humid climate shortly after extrusion (in contrast to the discrepancy between the reported nakhlite crystallization age and the age of their alteration products).…”

Section: Inferences Regarding Alterationmentioning

confidence: 99%

A combined electron microprobe (EMP) and Raman spectroscopic study of the alteration products in Martian meteorite MIL 03346

Kuebler

2013

JGR Planets

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We examine the secondary alteration products in MIL 03346 using Raman spectroscopic and electron microprobe traverses. Discussion focuses on the single olivine in ,177 supplemented with observations from ,168 and ,169. Traverses start at the rim and progress into the interior. Dark brown, nearly opaque, laihunite [Fe2+Fe3+2(SiO4)2] is present as overgrowths, and 20–50 µm veins of reddish‐brown stilpnomelane [(K,Na,Ca)4(Ti0.1,Al2.3,Fe3+35.5,Mn0.8,Mg9.3) (Si63Al9)(O,OH)206∗n(H2O)] occur inside the olivine. Stilpnomelane crosscuts and postdates the laihunite; veins are in sharp contact with the host olivine but lined by ~5 µm films of jarosite [KFe3+3(SO4)2(OH)6] from a later generation of alteration. An interstitial laihunite also hosts stilpnomelane. The most recent secondary phases are gypsum and bassanite in our X‐ray maps of ,168 and ,169. Ca‐sulfates were not observed in X‐ray maps of ,177 but were detected in our Raman point count. All sulfates are believed to be Martian. The groundmass of MIL indicates rapid cooling from elevated temperatures with fO2 near QFM. Reports of laihunite synthesis by olivine oxidation at elevated temperatures (100–800°C) suggest the overgrowths formed during consolidation. In terrestrial rocks, stilpnomelane is a product of late diagenesis to garnet‐grade metamorphism. In MIL, stilpnomelane appears to be a secondary phase formed at the lower end of this stability range, at conditions akin to diagenesis. Raman spectra indicate that the stilpnomelane, jarosite, and Ca‐sulfates are hydrated. The stilpnomelane contains Cl− and was followed by jarosite, a product of acid alteration, and the deposition of Ca‐sulfates and halide salts from more neutral chloride solutions.

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“…Multiple sites of on-land gas emission are reported to occur in the immediate vicinity of Lake Kyaninga, where dead animals such as birds, otters and python snakes have been found. This could be similar to the 'mazukus' phenomenon in the Nyaragongo area near Lake Kivu, D.R.Congo (Vaselli et al 2004, Smets et al 2010 where high concentrations of carbon dioxide are released.…”

Section: Discussionmentioning

confidence: 75%

Observations on the limnology and phytoplankton community of crater Lake Kyaninga (Uganda), with special attention to its diatom flora

Cocquyt¹,

Plisnier²,

Gelorini³

et al. 2010

Plecevo

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Background and aims - With a depth of at least 220 in, Lake Kyaninga is the deepest known maar crater lake in western Uganda. We studied its limnology and phytoplankton community to determine how the frequency and depth of water-column mixing influences nutrient cycling and seasonality in this aquatic ecosystem. Methods - Water-column temperature was measured continuously during a full annual cycle between August 2007 and August 2008. Other physical and chemical variables as well as diatom and other phytoplankton communities were investigated on three occasions, namely during the dry season in August of 2007 and 2008, and during the main wet season in April 2009. Key results and conclusions - The water column of Lake Kyaninga is permanently stratified (meromictic) below similar to 100 m depth. Above this depth, mixing frequency varies from daily (down to 8-12 m depth) over at least once per year (down to 39-47 m depth), to once in several years or decades (between 39-47 and similar to 100 m depth). Nutrient and chlorophyll concentrations as well as phytoplankton data classify the lake as low in aquatic productivity (oligotrophic). Its pelagic, open-water phytoplankton community is dominated by Cyanobacteria (blue-green algae) and Chlorophyta (green algae). Bacillariophyta (diatoms) contribute only a minor part of total phytoplankton biomass in both wet and dry seasons, and are characterized by an assemblage of small Nitzschia species. Epiphytic and epipelie diatoms are relatively few, because steep rocky crater slopes limit the littoral zone even though water-column transparency is high. The composition of recently deposited diatom assemblages preserved in offshore surface sediments gives a good, annually integrated representation of the present-day pelagic diatom community. The documented species richness of the diatom flora of Lake Kyaninga is moderate with about 150 taxa. Only similar to 17% of these are biogeographically restricted to tropical Africa; and most of these belong to the genus Nitzschia

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Dry gas vents (“mazuku”) in Goma region (North-Kivu, Democratic Republic of Congo): Formation and risk assessment

Cited by 41 publications

References 25 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

A combined electron microprobe (EMP) and Raman spectroscopic study of the alteration products in Martian meteorite MIL 03346

Observations on the limnology and phytoplankton community of crater Lake Kyaninga (Uganda), with special attention to its diatom flora

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Dry gas vents (“mazuku”) in Goma region (North-Kivu, Democratic Republic of Congo): Formation and risk assessment

Cited by 41 publications

References 25 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

A combined electron microprobe (EMP) and Raman spectroscopic study of the alteration products in Martian meteorite MIL 03346

Observations on the limnology and phytoplankton community of crater Lake Kyaninga (Uganda), with special attention to its diatom flora

Contact Info

Product

Resources

About

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