Geochemistry of gas emanations: A case study of the Réunion Hot Spot, Indian Ocean

Marty, Bernard; Meynier, Vincent; Nicolini, Eric-André; Griesshaber, Erika; Toutain, Jean

doi:10.1016/0883-2927(93)90030-k

Cited by 44 publications

(49 citation statements)

References 25 publications

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“…8 Diagram comparing carbon isotope ratios of CO 2 in Sierra Negra and Alcedo gases to selected volcanoes, geothermal systems, and common carbon sources (Rollison 1993). Sierra Negra and Alcedo gases plot at the depleted range of mantle compositions and isotopically resemble gases from the Hawaiian hot spot (e.g., Hilton et al 1998), some gases from the Reunion hot spot (Marty et al 1993), and gases from Pacaya, a high-alumina tholeiite volcano (P; Goff and McMurtry, in press). More silicic volcanoes, such as Galeras (G, andesite), St. Helens (SH, dacite), and Satsuma Iwo-jima (SI, rhyolite) are commonly depleted in d 13 C±CO 2 due to organic carbon contributions from the underlying slab.…”

Section: Gas Geochemistry Alcedomentioning

confidence: 98%

“…Interestingly, Valles caldera, which has produced more than 600 km 3 of predominately high-silica rhyolite from 1.62 Ma to 60 ka, presently discharges hydrothermal gases with obvious mantle affinities. Data sources: Vulcano, Usu, and White Island (Giggenbach and Matsuo 1991); Reunion (Marty et al 1993); Galeras, Kilauea, Moyuta, Pacaya, Satsuma, St. Helens, and Tecuamburro Goff and McMurtry, in press;D.R.Hilton, G.M. McMurtry, and F. Goff, unpublished data); Valles Caldera (Smith and Kennedy 1985;Goff and Gardner 1994).…”

Section: Gas Geochemistry Alcedomentioning

confidence: 99%

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Contrasting hydrothermal activity at Sierra Negra and Alcedo volcanoes, Galapagos Archipelago, Ecuador

Goff

McMurtry

Counce

et al. 2000

Bulletin of Volcanology

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Sierra Negra and Alcedo volcanoes are adjacent tholeiitic shields with summit calderas located on Isabela Island in the Galapagos Archipelago. Although basaltic eruptions have characterized the evolution of these volcanoes, Alcedo has produced minor volumes of rhyolite lavas and tephras dated at approximately 100 ka. Fumaroles and ephemeral acidsulfate seeps occur within the calderas of both volcanoes, whereas neutral-chloride and diluted steamheated hot springs are absent. Fumarolic activity inside Sierra Negra (Mina Azufral) is fault controlled along the west margin of a horst and discharge temperatures are^210 C (January to February 1995). Water content of the total gas is approximately 75 mol.%, and noncondensible gases consist of approximately 97 mol.% CO 2 and approximately 85% SO 2 of the total sulfur gas. Relative amounts of He, Ar, and N 2 show a distinct hot-spot signature ( 3 He/ 4 He=17.4 0.3 R A ). The d 13 C±CO 2 is approximately ± 3.6½ and d 34 S T is approximately +3.3½. The dD/ d 18 O of fumarole H 2 O indicates steam separation from local meteoric waters whose estimated minimum mean residence time from 3 H analyses is^40 years. Fumarolic activity at Alcedo is controlled by a caldera-margin fault containing at least seven hydrothermal explosion craters, and by an intracaldera rhyolite vent. Two explosion craters which formed in 1993±1994 produce approximately 15 m 3 /s of steam, yet discharge temperatures are^97 C. Water content of the total gas is 95±97 mol.%, noncondensible gas is 92±98 mol.% CO 2 , and sulfur gas is dominated by H 2 S. Relative amounts of He, Ar, and N 2 show extensive mixing between hot spot and air or air-saturated meteoric water components but the average > 3 He/ 4 He=15.5 0.4 R A . The d 13 C±CO 2 is approximately ± 3.5½ and d 34 S T is approximately ± 0.8½. The dD/ d 18 O of fumarole steam indicates separation from a homogeneous reservoir that is enriched 3±5½ in 18 O compared with local meteoric water. 3 H indicates that this reservoir water has a maximum mean residence time of approximately 400 years and empirical gas geothermometry indicates a reservoir temperature of 260±320 C. The intracaldera hydrothermal reservoir in Alcedo is probably capable of producing up to 150 MW; however, environmental concerns as well as lack of infrastructure and power users will limit the development of this resource.

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Section: Gas Geochemistry Alcedomentioning

confidence: 98%

Section: Gas Geochemistry Alcedomentioning

confidence: 99%

Contrasting hydrothermal activity at Sierra Negra and Alcedo volcanoes, Galapagos Archipelago, Ecuador

Goff

McMurtry

Counce

et al. 2000

Bulletin of Volcanology

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“…CO 2 concentration in analysed samples is consistent with field measurements and spans the range from 3986 to 52,618 ppm (0.4-5.3%). In the following, we keep the original model of Liuzzo et al (2015) where charcoal samples from Piton de la Fournaise ashes (−24.7‰ on average) are chosen as representative of the biogenic end-member Morandi et al, 2016) and measurements in summit fumaroles (−4.1‰) are considered representative of the magmatic δ 13 C end-member (Marty et al, 1993). The signature of the magmatic end member is also consistent with results from crushing and step-heating analyses of olivine grains from Piton Chisny's xenoliths that range from −4.6‰ up to −3.7‰ (Trull et al, 1993), with only one analysis at −10.2‰.…”

Section: Carbon Isotopic Composition Of Comentioning

confidence: 99%

“…At Piton de la Fournaise (La Réunion Island), diffuse flank CO 2 degassing is generally very weak (Seidel et al, 1988;Marty et al, 1993;Toutain et al, 2002;Liuzzo et al, 2015 ) and includes a significant biogenic component. This peculiar condition is explicable, most probably, by the tropical oceanic climate, which is marked by extreme precipitation rates and a high average temperature, allowing substratum degradation and fast vegetation development.…”

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confidence: 99%

Investigating the deepest part of a volcano plumbing system: Evidence for an active magma path below the western flank of Piton de la Fournaise (La Réunion Island)

Boudoire

Liuzzo

Muro

et al. 2017

Journal of Volcanology and Geothermal Research

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Peripheral diffuse degassing of CO 2 from the soil occurs across the western flank of Piton de la Fournaise volcano (La Réunion Island, Indian Ocean) along a narrow zone. In this area, carbon isotopic analysis on soil gas samples highlights significant mixing between magmatic and organic end-members. The zones with the strongest magmatic signature (highest δ 13 C) overlap spatial distribution of hypocenters recorded shortly before and during volcano reactivation and allow discriminating a N135° degassing lineament, with a minimum length of 11 km and 140 ± 20 m-width. Such orientation is in accordance with that of an old dyke network along the rift zone and with N120-130° and N140-155° lineaments related to the inheritance of oceanic lithosphere structures. Our findings show that this N135° lineament represents a preferential magmatic pathway for deep magma transfer below the volcano flank. Moreover, spatial distributions of recent eccentric cones indicate a well-founded possibility that future eruptions may by-pass the shallow plumbing system of the central area of the volcano, taking a lateral pathway along this structure. Our results also confirm that Piton de la Fournaise activity is linked to a laterally shifted plumbing system and represent a major improvement in identifying the main high-risk area on the densely populated western flank of the volcano.

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“…End member anoxic hot spring vent fluids, in both submarine and subaerial environments including nearby areas of Lake Towada, are known to con tain large amount of methane up to mmol/kg lev els (e.g., Yoshida, 1984;Welhan, 1988;Marty et al, 1993). Such an elevated concentration of emitted CH4 in immediate oxic vicinity of hot N himura et al spring vents may stimulate methane-oxidizing bacteria around vents.…”

Section: Resultsmentioning

confidence: 99%

Origin of 13C-enriched methane in the crater lake Towada, Japan.

et al. 1999

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Concentration and stable carbon isotopic composition (813C) of CH4 are determined in a water column of an 327 m deep oxic oligotrophic crater lake, Lake Towada in Japan. The results of CTD measurements show relatively high temperature and high conductivity in the lower part of the column, possibly derived from hot springs at the crater wall approximately 150 m deep. The vertical profile of CH4 concentration shows two sharp maxima of 68 and 69 nmol/kg at depths of 20 and 150 m, respectively. The 813C value of CH4 at 20 m is -55%oPDB, suggesting microbial production in and around the lake. In contrast, the 613C value of CH4 at 150 m is +11%oPDB, which suggests some secondary isotopic alternation processes peculiar to hot spring-derived CH4 in the oxic water column, such as rapid aerobic microbial oxidation.

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Geochemistry of gas emanations: A case study of the Réunion Hot Spot, Indian Ocean

Cited by 44 publications

References 25 publications

Contrasting hydrothermal activity at Sierra Negra and Alcedo volcanoes, Galapagos Archipelago, Ecuador

Contrasting hydrothermal activity at Sierra Negra and Alcedo volcanoes, Galapagos Archipelago, Ecuador

Investigating the deepest part of a volcano plumbing system: Evidence for an active magma path below the western flank of Piton de la Fournaise (La Réunion Island)

Origin of 13C-enriched methane in the crater lake Towada, Japan.

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