Format du dépôt |
Fichier |
Type de dépôt |
Article dans une revue |
Titre |
en
Petrological and experimental constraints on magma storage for large pumiceous eruptions in Dominica island (Lesser Antilles)
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Résumé |
en
The general question of the generation of large-volume silicic eruptions is here addressed through the experimental determination of the storage conditions of the primary magmas that generated ignimbritic eruptions at Dominica Island (Lesser Antilles) during the 24–51 ka period of time. The basal plinian fallouts and pumice pyroclastic flows from the large-volume (~ 5 km3 DRE) events of Layou, Roseau and Grand Fond were investigated, together with the smaller ignimbritic eruptions of Grand Bay and Grande Savane. All samples are dacitic (63–66 wt% SiO2) and contain ~ 30 vol% phenocrysts of plagioclase (~ 21 vol%), orthopyroxene (~ 5 vol%) and Fe-Ti oxides (< 1 vol%), in a rhyolitic matrix glass. The most differentiated samples contain additional amphibole (up to 5 vol%) and quartz. Crystallization experiments were performed starting from Layou and Roseau pumice samples at 800 to 900 °C, 200 to 400 MPa, ~ ΔNNO + 1 and for H2O-saturated and H2O-undersaturated conditions. The main phase contents, assemblages and compositions of both natural samples were reproduced experimentally at ~ 850 °C, ΔNNO + 0.6, 7–8 wt% melt H2O and ~ 400 MPa (~ 16 km depth) consistent with magma ponding at the mid-crustal discontinuity. There is also evidence of more differentiated magma batches that may reflect a plumbing system with a significant vertical extension. The relationships between the chamber depth, width and volume argue for eruptions that do not form collapse calderas, in agreement with field evidence. The erupted magma volumes in Dominica are more than five times larger than those emitted in the neighbouring islands (Martinique, Guadeloupe, Montserrat; < 1 km3), which may be explained by a locally extensional tectonic context that favoured assembly of large magma bodies, but also by the rarity of frequently draining upper crustal reservoirs (as evidenced on the neighbouring volcanic systems) that favoured deep accumulation of large volumes of magma during this period and time for differentiation to dacitic compositions.
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Auteur(s)
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Clara Solaro
1
, Caroline Martel
2, 3
, Rémi Champallier
2
, Georges Boudon
1
, Hélène Balcone-Boissard
4
, Michel Pichavant
2, 3
1
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
-
Institut national des sciences de l'Univers UMR_7154 ( 300045 )
;
-
Université de La Réunion UMR_7154 ( 300316 )
;
-
Institut de Physique du Globe de Paris UMR_7154 ( 300354 )
;
-
Centre National de la Recherche Scientifique UMR_7154 ( 441569 )
;
-
Université Paris Cité UMR_7154 ( 557826 )
2
ISTO -
Institut des Sciences de la Terre d'Orléans - UMR7327
( 187882 )
- Campus Géosciences 1A, rue de la Férollerie 45071 Orléans cedex 2
- France
-
Bureau de Recherches Géologiques et Minières UMR7327 ( 18404 )
;
-
Observatoire des Sciences de l'Univers en région Centre UAR3116 ( 197066 )
;
-
Institut national des sciences de l'Univers UAR3116 / UMS3116 ( 300045 )
;
-
Observatoire de Paris ( 300055 )
;
-
Université Paris Sciences et Lettres ( 564132 )
;
-
Université d'Orléans UAR3116 / UMS3116 ( 300297 )
;
-
Centre National de la Recherche Scientifique UAR3116 / UMS3116 ( 441569 )
;
-
Institut national des sciences de l'Univers UMR7327 ( 300045 )
;
-
Université d'Orléans UMR7327 ( 300297 )
;
-
Centre National de la Recherche Scientifique UMR7327 ( 441569 )
3
Magma - UMR7327
( 524463 )
- France
-
Institut des Sciences de la Terre d'Orléans - UMR7327 ( 187882 )
;
-
Bureau de Recherches Géologiques et Minières UMR7327 ( 18404 )
;
-
Observatoire des Sciences de l'Univers en région Centre UAR3116 ( 197066 )
;
-
Institut national des sciences de l'Univers UAR3116 / UMS3116 ( 300045 )
;
-
Observatoire de Paris ( 300055 )
;
-
Université Paris Sciences et Lettres ( 564132 )
;
-
Université d'Orléans UAR3116 / UMS3116 ( 300297 )
;
-
Centre National de la Recherche Scientifique UAR3116 / UMS3116 ( 441569 )
;
-
Institut national des sciences de l'Univers UMR7327 ( 300045 )
;
-
Université d'Orléans UMR7327 ( 300297 )
;
-
Centre National de la Recherche Scientifique UMR7327 ( 441569 )
4
iSTeP -
Institut des Sciences de la Terre de Paris
( 541927 )
- 4, place Jussieu BP CC129 75252 PARIS CEDEX 05
- France
-
Institut national des sciences de l'Univers UMR7193 ( 300045 )
;
-
Sorbonne Université ( 413221 )
;
-
Centre National de la Recherche Scientifique UMR7193 ( 441569 )
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Langue du document |
Anglais
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Nom de la revue |
|
Vulgarisation |
Non
|
Comité de lecture |
Oui
|
Audience |
Internationale
|
Date de publication |
2019-09
|
Volume |
81
|
Numéro |
9
|
Domaine(s) |
-
Planète et Univers [physics]
|
Financement |
-
French INSU Action Incitative
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Projet(s) Européen(s) |
-
VUELCO
- Volcanic unrest in Europe and Latin America: Phenomenology, eruption precursors, hazard forecast, and risk mitigation
Numéro CORDIS :
282759
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Mots-clés |
en
Dominica, Ignimbrite, Dacite, Phase equilibria, Storage conditions
|
DOI |
10.1007/s00445-019-1313-x |