Titre :

Mantle metasomatism influence on water contents in continental lithosphere: new constraints from garnet pyroxenite xenoliths (France & Cameroon volcanic provinces)

Auteur(s) :

Azevedo-Vannson, Samantha [Auteur]
Institut de minéralogie, de physique des matériaux et de cosmochimie [IMPMC]
Centre de Recherches Pétrographiques et Géochimiques [CRPG]
France, Lydéric [Auteur]
Centre de Recherches Pétrographiques et Géochimiques [CRPG]
Ingrin, Jannick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Chazot, Gilles [Auteur]
Laboratoire Géosciences Océan [LGO]

Titre de la manifestation scientifique :

Goldschmidt 2021

Ville :

Lyon

Pays :

France

Date de début de la manifestation scientifique :

2021-07-04

Mot(s)-clé(s) en anglais :

Nominally anhydrous minerals
Garnet pyroxenites
Hydroxyl
Mantle metasomatism
Adamawa Volcanic Plateau
French Massif Central

Discipline(s) HAL :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

Résumé en anglais : [en]

Quantifying water contents of the lithospheric mantle is key for our understanding of global geodynamics, mantle composition and related physical properties. Most of the mantle lithologies contain little water, but some ...
Lire la suite >Quantifying water contents of the lithospheric mantle is key for our understanding of global geodynamics, mantle composition and related physical properties. Most of the mantle lithologies contain little water, but some heterogeneities like pyroxenites, likely contain more water, and by their mineralogical assemblage melt at lower temperatures. The quantification of their water content brings new information about water distribution in the mantle. This study focuses on two continental lithospheric domains: the Massif Central (France) and the Adamawa Volcanic Plateau (Cameroon). Garnet pyroxenites in Adamawa Volcanic Plateau are more hydrated ([H2O]Cpx = 386-685 ppm; [H2O]Opx = 124-155 ppm; [H2O]Garnet < 0.5 ppm) than those of French Massif Central ([H2O]Cpx = 112-465 ppm; [H2O]Opx = 61-104 ppm; [H2O]Garnet < 0.5 ppm). These water concentrations are representative of lithospheric water (no water loss during xenolith ascent), however water content of French Massif Central pyroxenites have been modified by metasomatism. Pyroxenites have been dehydrated by a hot carbonatitic fluid, whereas rocks of Adamawa Volcanic Plateau were likely not affected by metasomatic events. In both regions, the metasomatic episodes modified the LREE contents (e.g., Ce). Consequently H2O/Ce ratio, which could be a good source tracer, might not be the most appropriate tool to identify pyroxenites implication in magmas genesis.Lire moins >

Langue :

Anglais

Comité de lecture :

Non

Audience :

Internationale

Établissement(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Équipe(s) de recherche :

Matériaux Terrestres et Planétaires

Date de dépôt :

2021-08-10T16:29:20Z
2021-08-27T06:10:50Z