Magma ascent and lava flow field emplacement during the 2018–2021 Fani Maoré deep-submarine eruption insights from lava vesicle textures
Pauline Verdurme
(1)
,
Lucia Gurioli
(1)
,
Oryaëlle Chevrel
(2, 1, 3)
,
Etienne Médard
(1)
,
Carole Berthod
(3)
,
Jean-Christophe Komorowski
(3)
,
Andrew Harris
(1)
,
Fabien Paquet
(4)
,
Cécile Cathalot
(5)
,
Nathalie Feuillet
(3)
,
Elodie Lebas
(3)
,
Emmanuel Rinnert
(5)
,
Jean-Pierre Donval
(5)
,
Isabelle Thinon
(4)
,
Christine Deplus
(3)
,
Patrick Bachèlery
(1)
Pauline Verdurme
- Fonction : Auteur
- PersonId : 1377334
- ORCID : 0000-0003-1928-0009
Lucia Gurioli
- Fonction : Auteur
- PersonId : 22120
- IdHAL : lucia-gurioli
- ORCID : 0000-0002-5066-5153
- IdRef : 175659346
Oryaëlle Chevrel
- Fonction : Auteur
- PersonId : 16003
- IdHAL : magdalena-oryaelle-chevrel
- ORCID : 0000-0003-1201-5448
Etienne Médard
- Fonction : Auteur
- PersonId : 21809
- IdHAL : etienne-medard
- ORCID : 0000-0002-7040-7442
- IdRef : 080648819
Carole Berthod
- Fonction : Auteur
- PersonId : 17093
- IdHAL : carole-berthod
- ORCID : 0000-0001-6890-5541
- IdRef : 199691231
Jean-Christophe Komorowski
- Fonction : Auteur
- PersonId : 752377
- IdHAL : jean-christophe-komorowski
- ORCID : 0000-0002-6874-786X
- IdRef : 164296913
Fabien Paquet
- Fonction : Auteur
- PersonId : 183777
- IdHAL : paquet-fabien
- ORCID : 0000-0003-2589-6758
Cécile Cathalot
- Fonction : Auteur
- PersonId : 768318
- ORCID : 0000-0002-0868-7201
- IdRef : 143026666
Elodie Lebas
- Fonction : Auteur
- PersonId : 1213268
- IdHAL : elodie-lebas
- ORCID : 0000-0003-1617-143X
Emmanuel Rinnert
- Fonction : Auteur
- PersonId : 756403
- ORCID : 0000-0003-1524-5505
- IdRef : 084438037
Isabelle Thinon
- Fonction : Auteur
- PersonId : 183599
- IdHAL : isabelle-thinon
- ORCID : 0000-0001-8358-2699
- IdRef : 060970219
Christine Deplus
- Fonction : Auteur
- PersonId : 741849
- IdHAL : christine-deplus
- ORCID : 0000-0003-3689-3704
- IdRef : 032315171
Patrick Bachèlery
- Fonction : Auteur
- PersonId : 169906
- IdHAL : patrick-bachelery
- ORCID : 0000-0002-0108-5486
- IdRef : 068733887
Résumé
The 2018–2021 Fani Maor´e submarine eruption (offshore of Mayotte, Mozambique Channel) extruded a bulk volume of ~6.5 km3 of basanite magma onto the seafloor at a depth of 3300 m, with effusion rates ranging from 150 to 200 m3/s in the first year of the eruption, to less than 11 m3/s in the final months. Six oceanographic campaigns provided a large sample set covering the entire flow field at high spatial and temporal resolution.
These samples allow us to precisely track syn-eruptive degassing processes through quantification of textural parameters including porosity, pore connectivity, vesicle number density (NV) and vesicle size distributions (VSD). Three different textural facies have been distinguished. (1) Vesicular lavas (average porosity of 35%) display unimodal VSDs, high NV (14–214 mm 3), and small and spherical vesicles. (2) Lavas with intermediate porosities (25%) have scarce small vesicles, VSDs shifted towards larger vesicles, and low NV (0.2–39 mm 3). (3) Dense lavas with low porosities (14%) display bimodal VSDs distribution, a dominant mode of small vesicles, and low NV (0–87 mm 3). The early phase of activity (Phase 1, June 2018 – May 2019) built the main edifice and was fed by rapid ascent and closed-system degassing of volatile-rich magma ascending from a deep reservoir to the seafloor (Facies 1). Distal samples collected from lava flows emitted during Phase 2, between June and July 2019, show large and irregular shape vesicles mostly related to bubble growth and coalescence, and outgassing during emplacement (Facies 2). These lavas are interpreted to be emplaced during extension of a lava tube system which began to develop during Phase 1. The final phase (Phase 3, August 2019 – January 2021) was associated with lava effusion located at the northwest lava flow front, 6 km from the summit. Phase 3 involved a more degassed magma due to the increase in the length of the magma pathway (Facies 3). Phase 3 lavas were also extremely outgassed and associated with construction of a new complex lava flow field with tumuli and multiple ephemeral vents (lava breakouts). The heterogeneous textures within the studied samples reflect changing ascent and effusion rates with time, leading to emplacement of lava flows which varied depending on the degree of degassing and effusion rate. We conclude that emplacement of the Fani Maor´e large submarine lava flow fields developed through extensive and prolonged tube systems this being supported by the high effusion
rates.
Domaines
Planète et Univers [physics]Format du dépôt | Fichier |
---|---|
Type de dépôt | Article dans une revue |
Titre |
en
Magma ascent and lava flow field emplacement during the 2018–2021 Fani Maoré deep-submarine eruption insights from lava vesicle textures
|
Résumé |
en
The 2018–2021 Fani Maor´e submarine eruption (offshore of Mayotte, Mozambique Channel) extruded a bulk volume of ~6.5 km3 of basanite magma onto the seafloor at a depth of 3300 m, with effusion rates ranging from 150 to 200 m3/s in the first year of the eruption, to less than 11 m3/s in the final months. Six oceanographic campaigns provided a large sample set covering the entire flow field at high spatial and temporal resolution.
These samples allow us to precisely track syn-eruptive degassing processes through quantification of textural parameters including porosity, pore connectivity, vesicle number density (NV) and vesicle size distributions (VSD). Three different textural facies have been distinguished. (1) Vesicular lavas (average porosity of 35%) display unimodal VSDs, high NV (14–214 mm 3), and small and spherical vesicles. (2) Lavas with intermediate porosities (25%) have scarce small vesicles, VSDs shifted towards larger vesicles, and low NV (0.2–39 mm 3). (3) Dense lavas with low porosities (14%) display bimodal VSDs distribution, a dominant mode of small vesicles, and low NV (0–87 mm 3). The early phase of activity (Phase 1, June 2018 – May 2019) built the main edifice and was fed by rapid ascent and closed-system degassing of volatile-rich magma ascending from a deep reservoir to the seafloor (Facies 1). Distal samples collected from lava flows emitted during Phase 2, between June and July 2019, show large and irregular shape vesicles mostly related to bubble growth and coalescence, and outgassing during emplacement (Facies 2). These lavas are interpreted to be emplaced during extension of a lava tube system which began to develop during Phase 1. The final phase (Phase 3, August 2019 – January 2021) was associated with lava effusion located at the northwest lava flow front, 6 km from the summit. Phase 3 involved a more degassed magma due to the increase in the length of the magma pathway (Facies 3). Phase 3 lavas were also extremely outgassed and associated with construction of a new complex lava flow field with tumuli and multiple ephemeral vents (lava breakouts). The heterogeneous textures within the studied samples reflect changing ascent and effusion rates with time, leading to emplacement of lava flows which varied depending on the degree of degassing and effusion rate. We conclude that emplacement of the Fani Maor´e large submarine lava flow fields developed through extensive and prolonged tube systems this being supported by the high effusion
rates.
|
Auteur(s) |
Pauline Verdurme
1
, Lucia Gurioli
1
, Oryaëlle Chevrel
2, 1, 3
, Etienne Médard
1
, Carole Berthod
3
, Jean-Christophe Komorowski
3
, Andrew Harris
1
, Fabien Paquet
4
, Cécile Cathalot
5
, Nathalie Feuillet
3
, Elodie Lebas
3
, Emmanuel Rinnert
5
, Jean-Pierre Donval
5
, Isabelle Thinon
4
, Christine Deplus
3
, Patrick Bachèlery
1
1
LMV -
Laboratoire Magmas et Volcans
( 1063727 )
- Campus Universitaire des Cézeaux, 6 Avenue Blaise Pascal, 63178 Aubière Cedex
- France
2
OVPF -
Observatoire Volcanologique du Piton de la Fournaise
( 262384 )
- 14 RN3-Km27, 97418, La Plaine des Cafres, La Réunion, France
- La Réunion
3
IPGP (UMR_7154) -
Institut de Physique du Globe de Paris
( 1005035 )
- 1 rue Jussieu, 75238 Paris cedex 05 et Bât. Lamarck A case postale 7011, 75205 Paris CEDEX 13
- France
4
BRGM -
Bureau de Recherches Géologiques et Minières
( 18404 )
- regroupe le site d'Orléans et l'ensemble des Directions régionales sous une seule et même affiliation. Ne pas décliner de sous-structures locales
- France
5
GEO-OCEAN -
Geo-Ocean
( 1083595 )
- Geo-Ocean - UMR6538 - Place Nicolas Copernic - 29280 PLOUZANE
- France
|
Licence |
Paternité - Pas d'utilisation commerciale - Pas de modification
|
Langue du document |
Anglais
|
Nom de la revue |
|
Date de publication |
2024-06
|
Volume |
636
|
Page/Identifiant |
118720
|
Vulgarisation |
Non
|
Comité de lecture |
Oui
|
Audience |
Internationale
|
Domaine(s) |
|
Projet(s) ANR |
|
Référence interne |
|
DOI | 10.1016/j.epsl.2024.118720 |
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Fichier sous embargo
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Fin d'embargo le dimanche 15 décembre 2024
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