Mantle xenolith-bearing phonolites and basanites feed the active volcanic ridge of Mayotte (Comoros archipelago, SW Indian Ocean)

Type Article
Date 2021-10
Language English
Author(s) Berthod CaroleORCID1, Médard Etienne1, Di Muro Andrea2, 3, Hassen Ali Théo1, Gurioli Lucia1, Chauvel Catherine3, Komorowski Jean-Christophe3, Bachèlery Patrick1, Peltier Aline2, 3, Benbakkar Mhammed1, Devidal Jean-Luc1, Besson Pascale3, Le Friant Anne3, Deplus Christine3, Nowak Sophie3, Thinon Isabelle4, Burckel Pierre3, Hidalgo Samia3, Feuillet Nathalie3, Jorry StephanORCID5, Fouquet Yves5
Affiliation(s) 1 : Laboratoire Magmas et Volcans, Université Clermont Auvergne, CNRS, IRD, OPGC, Clermont-Ferrand, France
2 : Observatoire Volcanologique du Piton de la Fournaise, Institut de physique du globe de Paris, 97418, La Plaine des Cafres, France
3 : Institut de physique du globe de Paris, CNRS, Université de Paris, 75005, Paris, France
4 : BRGM, French Geological Survey, 3 avenue Claude Guillemin, BP36009, 45 060, Cédex 2, Orléans, France
5 : Ifremer, Unité Géosciences Marines, 29280, Plouzané, France
Source Contributions To Mineralogy And Petrology (0010-7999) (Springer Science and Business Media LLC), 2021-10 , Vol. 176 , N. 10 , P. 75 (24p.)
DOI 10.1007/s00410-021-01833-1
WOS© Times Cited 22
Keyword(s) Mayotte, Basanite, Phonolite, Magmatic system, Fractional crystallization

Since 2018, the submarine east flank of Mayotte Island (Comoros archipelago) is the site of a major eruption located at 3.5 km depth bsl on a WNW-ESE volcanic ridge. Samples brought by oceanographic cruises carried out to monitor this seismo-volcanic crisis indicate that this volcanic ridge is built by a bimodal sodic alkaline magmatic series that includes basanites and phonolites. A petrological study of dredged samples allowed us to image the magmatic system feeding the volcanic ridge and to determine the link between basanitic and phonolitic magmas. The magmatic system feeding the volcanic ridge comprises multiple levels of magma storage. Basanitic magmas generated at 80–100 km mantle depth are stored in two or more deep reservoirs (≥ 37 km) and then in shallower basanitic and phonolitic lenses located close to the Moho interface before rising the surface. This study identifies three possible scenarios: (1) the deep basanitic magma rises directly and quickly to the surface from the deep mantle reservoir (as is currently happening 60 km offshore), (2) the basanitic magma stalls in a shallower reservoir near the Moho before resuming its ascent toward the surface and erupting as porphyritic basanite, (3) the basanitic magma stops and evolves to phonolite in these sub-crustal reservoirs. The phonolitic lavas are produced by approximately 80% fractional crystallization (34% clinopyroxene, 30% anorthoclase feldspar, 15.5% magnetite, 12.5% olivine, 5% apatite and 4% ilmenite) of a hydrous basanitic magma at mantle depths (P > 0.6 GPa) under reduced oxygen fugacity (~ FMQ-1). In this third scenario, the phonolitic magma might be reactivated by the arrival of a new batch of deeper basanitic magma.

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Berthod Carole, Médard Etienne, Di Muro Andrea, Hassen Ali Théo, Gurioli Lucia, Chauvel Catherine, Komorowski Jean-Christophe, Bachèlery Patrick, Peltier Aline, Benbakkar Mhammed, Devidal Jean-Luc, Besson Pascale, Le Friant Anne, Deplus Christine, Nowak Sophie, Thinon Isabelle, Burckel Pierre, Hidalgo Samia, Feuillet Nathalie, Jorry Stephan, Fouquet Yves (2021). Mantle xenolith-bearing phonolites and basanites feed the active volcanic ridge of Mayotte (Comoros archipelago, SW Indian Ocean). Contributions To Mineralogy And Petrology, 176(10), 75 (24p.). Publisher's official version : , Open Access version :