Hydrogen diffusion in hydrous minerals: ...
Document type :
Autre communication scientifique (congrès sans actes - poster - séminaire...): Poster
Permalink :
Title :
Hydrogen diffusion in hydrous minerals: revised closure temperatures for isotopic exchange during fluid-rock interactions
Author(s) :
Reynard, B [Auteur]
Jonfal, J [Auteur]
Ganzhorn, A -C [Auteur]
Ingrin, Jannick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Jonfal, J [Auteur]
Ganzhorn, A -C [Auteur]
Ingrin, Jannick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Conference title :
Experimental Mineralogy, Petroly and Geochemistry
City :
Milano
Country :
Italie
Start date of the conference :
2023-06-15
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
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]
Interactions between aqueous fluids and rocks occur in a broad range of contexts ranging from hydrothermal alteration to regional metamorphism on Earth and parent body metamorphism in meteorites. Tracking these processes ...
Show more >Interactions between aqueous fluids and rocks occur in a broad range of contexts ranging from hydrothermal alteration to regional metamorphism on Earth and parent body metamorphism in meteorites. Tracking these processes and understanding their reaction kinetics require a precise knowledge of the diffusion of water in rocks, and of isotope fractionation in major hydrous minerals. Deuterium-hydrogen exchange between amphibole (tremolite), vesuvianite minerals and deuterated gas (D2) was experimentally investigated in a furnace over the temperature range of 400-550°C at ambient pressure. D/(D+H) ratios in exchanged mineral grains were mapped using Raman spectroscopy. Deuterium hydrogen exchange proceeded by deuterium hydrogen lattice diffusion, and also along cleavage in amphibole. Arrhenius relations for deuterium-hydrogen lattice-diffusion coefficients were derived from the new dataset. Values of activation energy (E) is 198 ±11 (1s) kJ/mol and logD0 -3.0 ± 0.8 are obtained for vesuvianite, and 133 ± 13 kJ/mol, and -9.2 ± 0.9 for tremolite. Activation energy for tremolite is a minimum value and is likely higher and similar to those in the range 170-200 kJ/mol inferred for antigorite, chlorite and vesuvianite using similar methods. Diffusion coefficients obtained with bulk isotopic analysis for amphiboles and epidotezoisite are much higher and display lower apparent activation energy (<80 kJ/mol) than those inferred from spatially resolved diffusion profiles obtained using punctual methods (Raman, NanoSIMS). Overestimation of diffusion coefficients by bulk analysis is attributed to unverified assumptions on grain size for minerals presenting easy cleavage (amphiboles, epidote, ...) that decrease effective grain size and increase surface for diffusive exchange during the experiments. Minerals like vesuvianite and tourmaline that have no cleavage planes show low diffusion coefficients from both spatially resolved and bulk analytical methods. Extrapolation of these new diffusion laws to low temperatures yields closure temperature of hydrogen isotope diffusion in hydrous minerals that are much higher than previously estimated. Hydrous minerals may thus retain information on relatively high temperature metamorphism on parent bodies of carbonaceous chondrites, and could display hydrogen isotope zoning in terrestrial rocks that may record the history of metamorphic fluid interactions and volcanic eruptions.Show less >
Show more >Interactions between aqueous fluids and rocks occur in a broad range of contexts ranging from hydrothermal alteration to regional metamorphism on Earth and parent body metamorphism in meteorites. Tracking these processes and understanding their reaction kinetics require a precise knowledge of the diffusion of water in rocks, and of isotope fractionation in major hydrous minerals. Deuterium-hydrogen exchange between amphibole (tremolite), vesuvianite minerals and deuterated gas (D2) was experimentally investigated in a furnace over the temperature range of 400-550°C at ambient pressure. D/(D+H) ratios in exchanged mineral grains were mapped using Raman spectroscopy. Deuterium hydrogen exchange proceeded by deuterium hydrogen lattice diffusion, and also along cleavage in amphibole. Arrhenius relations for deuterium-hydrogen lattice-diffusion coefficients were derived from the new dataset. Values of activation energy (E) is 198 ±11 (1s) kJ/mol and logD0 -3.0 ± 0.8 are obtained for vesuvianite, and 133 ± 13 kJ/mol, and -9.2 ± 0.9 for tremolite. Activation energy for tremolite is a minimum value and is likely higher and similar to those in the range 170-200 kJ/mol inferred for antigorite, chlorite and vesuvianite using similar methods. Diffusion coefficients obtained with bulk isotopic analysis for amphiboles and epidotezoisite are much higher and display lower apparent activation energy (<80 kJ/mol) than those inferred from spatially resolved diffusion profiles obtained using punctual methods (Raman, NanoSIMS). Overestimation of diffusion coefficients by bulk analysis is attributed to unverified assumptions on grain size for minerals presenting easy cleavage (amphiboles, epidote, ...) that decrease effective grain size and increase surface for diffusive exchange during the experiments. Minerals like vesuvianite and tourmaline that have no cleavage planes show low diffusion coefficients from both spatially resolved and bulk analytical methods. Extrapolation of these new diffusion laws to low temperatures yields closure temperature of hydrogen isotope diffusion in hydrous minerals that are much higher than previously estimated. Hydrous minerals may thus retain information on relatively high temperature metamorphism on parent bodies of carbonaceous chondrites, and could display hydrogen isotope zoning in terrestrial rocks that may record the history of metamorphic fluid interactions and volcanic eruptions.Show less >
Language :
Anglais
Peer reviewed article :
Oui
Audience :
Internationale
Popular science :
Non
Administrative institution(s) :
Université de Lille
CNRS
INRAE
ENSCL
CNRS
INRAE
ENSCL
Collections :
Research team(s) :
Matériaux Terrestres et Planétaires
Matériaux Terrestres et Planétaires
Matériaux Terrestres et Planétaires
Submission date :
2023-06-02T14:03:21Z
2023-06-09T07:16:56Z
2023-06-19T07:27:36Z
2023-06-09T07:16:56Z
2023-06-19T07:27:36Z