Titre :

Identification of two distinct OH infrared signatures in pyroxenes from pyroxenite xenoliths

Auteur(s) :

Ingrin, Jannick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Azevedo-Vannson, Samantha [Auteur]
Centre de Recherches Pétrographiques et Géochimiques [CRPG]
France, Lydéric [Auteur]
Centre de Recherches Pétrographiques et Géochimiques [CRPG]

Titre de la manifestation scientifique :

EGU General Assembly 2019

Ville :

Vienne (Austria)

Pays :

Autriche

Date de début de la manifestation scientifique :

2019-04-07

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]

Water concentration in pyroxenes from mantle xenoliths is generally used to trace the water content of lithospheric mantle. However, the infrared OH signatures recorded by pyroxenes provides also important information on ...
Lire la suite >Water concentration in pyroxenes from mantle xenoliths is generally used to trace the water content of lithospheric mantle. However, the infrared OH signatures recorded by pyroxenes provides also important information on their previous equilibrium. We present results of infrared analyses of garnet pyroxenites xenoliths, two from the French Massif Central (Devès, FMC) and two from Cameroon (Youkou Maar, Adamaou, Africa). The FMC pyroxenites have low water content and present dominant OH bands at 3595, 3517 cm−1 and 3571, 3517 cm−1 for cpx and opx, respectively. The pyroxenites from Cameroon have high water content and have dominant bands at 3635, 3445 cm−1 and 3602, 3417 cm−1 for cpx and opx. Like for OH spectra from peridotite xenoliths from Nógrád-Gömör (Hungary), it was possible to isolate two distinct end-member spectra in pyroxenes (Patkó et al. 2019). Spectra signatures of cpx and opx are correlated, showing that they have both recorded the same events. The two end-members spectra clearly point out for two distinct spectral signatures related to distinct OH defects configurations. The pyroxenites from FMC have crystallized at higher temperature than those of Cameroon (1050°C versus 950°C; France et al. 2015). These results suggest that the FMC pyroxenites have also crystallized in drier conditions than the ones from Cameroon or have experienced dry metasomatism after their crystallization. References France, L. et al. (2015) Mantle refertilization and magmatism in old orogenic regions: The role of late-orogenic pyroxenites. Lithos, 232, 49-75. Patkó L. et al. (2019) Extremely low structural hydroxyl contents in upper mantle xenoliths from the Nógrád-Gömör volcanic field (northern Pannonian Basin): Geodynamic implications and the role of post-eruptive re-equilibration. Chemical Geology, https://doi.org/10.1016/j.chemgeo2018.12.017.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Établissement(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Équipe(s) de recherche :

Matériaux Terrestres et Planétaires

Date de dépôt :

2023-09-07T14:53:17Z
2023-09-07T17:55:31Z