The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprints
The Comoros archipelago is an active geodynamic region located in the Mozambique Channel between East continental Africa and Madagascar. The archipelago results from intra-plate volcanism, the most recent eruptions having occurred on the youngest island of Grande Comore and on the oldest one of Mayo...
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Académie des sciences
2022-09-01
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| Series: | Comptes Rendus. Géoscience |
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| Online Access: | https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.148/ |
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| author | Liuzzo, Marco Di Muro, Andrea Rizzo, Andrea Luca Grassa, Fausto Coltorti, Massimo Ader, Magali |
| author_facet | Liuzzo, Marco Di Muro, Andrea Rizzo, Andrea Luca Grassa, Fausto Coltorti, Massimo Ader, Magali |
| author_sort | Liuzzo, Marco |
| collection | DOAJ |
| description | The Comoros archipelago is an active geodynamic region located in the Mozambique Channel between East continental Africa and Madagascar. The archipelago results from intra-plate volcanism, the most recent eruptions having occurred on the youngest island of Grande Comore and on the oldest one of Mayotte. Since 2018, the eastern submarine flank of Mayotte has been the site of one of the largest recent eruptive events on Earth in terms of erupted lava volume. On land, the most recent volcanic activity occurred in Holocene on the eastern side of Mayotte, corresponding to the small Petite Terre Island, where two main and persistent gas seep areas are present (Airport Beach, namely BAS, and Dziani Dzaha intracrateric lake). The large submarine eruption at the feet of Mayotte (50 km offshore; 3.5 km b.s.l.) is associated with deep (mantle level) seismic activity closer to the coast (5–15 km offshore) possibly corresponding to a single and large magmatic plumbing system. Our study aims at characterizing the chemical and isotopic composition of gas seeps on land and assesses their potential link with the magmatic plumbing system feeding the Mayotte volcanic ridge and the recent submarine activity. Data from bubbling gases collected between 2018 and 2021 are discussed and compared with older datasets acquired between 2005 and 2016 from different research teams. The relation between $\mbox {}^{3}\mathrm{He}/\mbox {}^{4}\mathrm{He}$ and $\delta ^{13}\mathrm{C}$-$\mathrm{CO}_{2}$ shows a clear magmatic origin for Mayotte bubbling gases, while the variable proportions and isotopic signature of $\mathrm{CH}_{4}$ is related to the occurrence of both biogenic and abiogenic sources of methane. Our new dataset points to a time-decreasing influence of the recent seismo-volcanic activity at Mayotte on the composition of hydrothermal fluids on land, whose equilibrium temperature steadily decreases since 2018. The increased knowledge on the gas-geochemistry at Mayotte makes the results of this work of potential support for volcanic and environmental monitoring programs. |
| first_indexed | 2024-03-10T07:22:34Z |
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| institution | Directory Open Access Journal |
| issn | 1778-7025 |
| language | English |
| last_indexed | 2024-03-10T07:22:34Z |
| publishDate | 2022-09-01 |
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| spelling | doaj.art-d1f6ae90afcc48b9b86d3398e216f7fd2023-11-22T14:29:44ZengAcadémie des sciencesComptes Rendus. Géoscience1778-70252022-09-01354S227529810.5802/crgeos.14810.5802/crgeos.148The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprintsLiuzzo, Marco0https://orcid.org/0000-0002-3099-7505Di Muro, Andrea1https://orcid.org/0000-0002-7635-1283Rizzo, Andrea Luca2https://orcid.org/0000-0003-2225-3781Grassa, Fausto3https://orcid.org/0000-0001-5043-792XColtorti, Massimo4https://orcid.org/0000-0002-7481-8097Ader, Magali5https://orcid.org/0000-0002-9239-1509Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Italy; Università di Ferrara, Dipartimento di Fisica e Scienze della Terra, ItalyObservatoire volcanologique du Piton de la Fournaise, Institut de physique du globe de Paris, F-97418 La Plaine des Cafres, France; Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris, FranceIstituto Nazionale di Geofisica e Vulcanologia, Sezione di Milano, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, ItalyIstituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, ItalyUniversità di Ferrara, Dipartimento di Fisica e Scienze della Terra, ItalyUniversité de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris, FranceThe Comoros archipelago is an active geodynamic region located in the Mozambique Channel between East continental Africa and Madagascar. The archipelago results from intra-plate volcanism, the most recent eruptions having occurred on the youngest island of Grande Comore and on the oldest one of Mayotte. Since 2018, the eastern submarine flank of Mayotte has been the site of one of the largest recent eruptive events on Earth in terms of erupted lava volume. On land, the most recent volcanic activity occurred in Holocene on the eastern side of Mayotte, corresponding to the small Petite Terre Island, where two main and persistent gas seep areas are present (Airport Beach, namely BAS, and Dziani Dzaha intracrateric lake). The large submarine eruption at the feet of Mayotte (50 km offshore; 3.5 km b.s.l.) is associated with deep (mantle level) seismic activity closer to the coast (5–15 km offshore) possibly corresponding to a single and large magmatic plumbing system. Our study aims at characterizing the chemical and isotopic composition of gas seeps on land and assesses their potential link with the magmatic plumbing system feeding the Mayotte volcanic ridge and the recent submarine activity. Data from bubbling gases collected between 2018 and 2021 are discussed and compared with older datasets acquired between 2005 and 2016 from different research teams. The relation between $\mbox {}^{3}\mathrm{He}/\mbox {}^{4}\mathrm{He}$ and $\delta ^{13}\mathrm{C}$-$\mathrm{CO}_{2}$ shows a clear magmatic origin for Mayotte bubbling gases, while the variable proportions and isotopic signature of $\mathrm{CH}_{4}$ is related to the occurrence of both biogenic and abiogenic sources of methane. Our new dataset points to a time-decreasing influence of the recent seismo-volcanic activity at Mayotte on the composition of hydrothermal fluids on land, whose equilibrium temperature steadily decreases since 2018. The increased knowledge on the gas-geochemistry at Mayotte makes the results of this work of potential support for volcanic and environmental monitoring programs.https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.148/Gas-geochemistryHydrothermal systemBiogenic vs abiogenic CO<sub>2</sub> & CH<sub>4</sub>Stable and noble gas isotopesMayotteComoros |
| spellingShingle | Liuzzo, Marco Di Muro, Andrea Rizzo, Andrea Luca Grassa, Fausto Coltorti, Massimo Ader, Magali The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprints Comptes Rendus. Géoscience Gas-geochemistry Hydrothermal system Biogenic vs abiogenic CO<sub>2</sub> & CH<sub>4</sub> Stable and noble gas isotopes Mayotte Comoros |
| title | The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprints |
| title_full | The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprints |
| title_fullStr | The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprints |
| title_full_unstemmed | The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprints |
| title_short | The composition of gas emissions at Petite Terre (Mayotte, Comoros): inference on magmatic fingerprints |
| title_sort | composition of gas emissions at petite terre mayotte comoros inference on magmatic fingerprints |
| topic | Gas-geochemistry Hydrothermal system Biogenic vs abiogenic CO<sub>2</sub> & CH<sub>4</sub> Stable and noble gas isotopes Mayotte Comoros |
| url | https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.148/ |
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