Title :

A new probe for studying lithosphere interaction with volatiles: OH-signatures of pyroxenes

Author(s) :

Ingrin, Jannick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207

Conference title :

International Symposium on Deep Earth Exploration and Practices (DEEP2021)

Conference organizers(s) :

China Geological Survey of the Ministry of Natural Resources of China
National Natural Science Foundation of China

City :

Beijing

Country :

Chine

Start date of the conference :

2021-11-01

HAL domain(s) :

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

English abstract : [en]

Depending of their metasomatic history or geodynamic origin OH stretching bands of lithospheric pyroxenes in the frequency range 3000 – 3700 cm-1 show different signatures. Pyroxenes from continental lithosphere having ...
Show more >Depending of their metasomatic history or geodynamic origin OH stretching bands of lithospheric pyroxenes in the frequency range 3000 – 3700 cm-1 show different signatures. Pyroxenes from continental lithosphere having undergone “wet” metasomatism have distinct signature compared to continental pyroxenes having undergone “dry” metasomatism. Pyroxenes from oceanic lithosphere have a third type of signature and a fourth type can be identified in xenoliths from island-arcs. We present recent analyses of xenoliths and a review of the literature showing that the phenomenon is widely distributed among continents and oceans. It shows that the phenomenon affects simultaneously opx and cpx and pyroxenes from various lithologies: peridotites, pyroxenites and granulites. For instance, in continental lithosphere, type I signature with OH bands at 3600 and 3415 cm-1 for opx and 3635 and 3445 cm-1 for cpx dominate pyroxenes affected by “wet” metasomatism; while type II with OH bands at 3570 and 3515 cm-1 for opx and 3595 and 3515 cm-1 for cpx dominate pyroxenes affected by “dry” metasomatism. Opxs from oceanic lithosphere have signatures of type III with OH spectra dominated by the band at 3415 cm-1 with a smaller contribution of the bands at 3520, 3570 and 3200 cm-1. Island arc xenoliths show two types of signatures type I but also a type IV with OH spectra dominated by the bands at 3545, 3520, 3300 and 3060 cm-1. It is also interesting to notice that most xenoliths from hot spots directly under oceanic lithosphere have pyroxenes with type I signature. Hot spot modified the OH-signatures of the oceanic lithospheric mantle . In all these observations it was not possible to correlate the signatures with a specific major, minor or trace element and the exact nature of the signatures remains to be identified. Nevertheless, these OH signatures are representative of specific lithospheric events and offer a potential new benchmark for the study of lithosphere-fluid interactions.Show less >

Language :

Anglais

Peer reviewed article :

Non

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Terrestres et Planétaires

Submission date :

2021-11-04T16:09:39Z
2021-11-04T16:48:38Z