Grain-scale feedback between deformation mechanisms and metamorphic reactions: Dissolution-precipitation processes in the lower crust (Kågen gabbros).
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| Title: | Grain-scale feedback between deformation mechanisms and metamorphic reactions: Dissolution-precipitation processes in the lower crust (Kågen gabbros). |
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| Authors: | Mérit, Louise1 (AUTHOR) louise.merit@sorbonne-universite.fr, Soret, Mathieu2 (AUTHOR), Dubacq, Benoît1 (AUTHOR), Agard, Philippe1,3 (AUTHOR), Précigout, Jacques4 (AUTHOR), Stünitz, Holger4,5 (AUTHOR) |
| Source: | Earth & Planetary Science Letters. Apr2025, Vol. 656, pN.PAG-N.PAG. 1p. |
| Subjects: | Strains & stresses (Mechanics), Material plasticity, Shear zones, Metamorphic rocks, Chemical equilibrium |
| Abstract: | • In kågen gabbros, strain is mainly accommodated by dissolution precipitation creep. • Homogenization of reactions is controlled at a scale of ∼100 µm. • Chemical equilibrium is reached locally, residual zoning reflects reaction progress. • Rheological laws should integrate dissolution-precipitation processes. Strain localization within crustal shear zones involves intricate feedback between deformation mechanisms, metamorphic reactions and fluid circulation. Despite evidence that these high-deformation zones proceed at least partly through dissolution-precipitation creep, available creep laws so far only account for dislocation creep and/or solid-state diffusion processes. Deciphering the role and the contribution of dissolution-precipitation creep to strain accommodation is now required to further understand the rheological behavior of polymineralic crustal rocks. This study combines high-resolution microstructural and compositional analytical techniques to track the progressive deformation of the Kågen metagabbros, at and below grain scale. The Kågen metagabbros preserved a strain and re-equilibration gradient over outcrop-scale, where metamorphic re-equilibrations and fluid infiltration took place at constant pressure and temperature representative of lower crustal conditions (ca. 1 GPa - 660 ± 25 °C). The comparison and quantification of chemical and microstructural information in this shear zone, through pixel-per-pixel and grain-per-grain correlated EPMA and EBSD maps, enables tracking grain-scale deformation mechanisms as well as the interplay between grain size reduction, mineral reactions, phase mixing and material transfer. Dissolution-precipitation creep appears dominant for strain accommodation in the Kågen metagabbros shear zone. As deformation progresses, nucleation of new metamorphic minerals (clinopyroxene, plagioclase, amphibole) allow for grain size reduction and compositional homogenization through dissolution, transport and precipitation processes associated with fluid ingression along grain boundaries. Intracrystalline plastic deformation is here insignificant for strain accommodation. Thermodynamic modeling and textural analysis reveal that re-equilibration processes are spatially controlled by microdomains where equilibrium is reached locally, on a scale of ∼100 µm. This study calls for integrating reactions, dissolution-precipitation processes, fluids and polymineralic assemblages into rheological laws for a reliable assessment of the mechanical evolution of metamorphic rocks. [ABSTRACT FROM AUTHOR] |
| Copyright of Earth & Planetary Science Letters is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 183503942 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Grain-scale feedback between deformation mechanisms and metamorphic reactions: Dissolution-precipitation processes in the lower crust (Kågen gabbros). – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Mérit%2C+Louise%22">Mérit, Louise</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> louise.merit@sorbonne-universite.fr</i><br /><searchLink fieldCode="AR" term="%22Soret%2C+Mathieu%22">Soret, Mathieu</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Dubacq%2C+Benoît%22">Dubacq, Benoît</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Agard%2C+Philippe%22">Agard, Philippe</searchLink><relatesTo>1,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Précigout%2C+Jacques%22">Précigout, Jacques</searchLink><relatesTo>4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Stünitz%2C+Holger%22">Stünitz, Holger</searchLink><relatesTo>4,5</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Earth+%26+Planetary+Science+Letters%22">Earth & Planetary Science Letters</searchLink>. Apr2025, Vol. 656, pN.PAG-N.PAG. 1p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Strains+%26+stresses+%28Mechanics%29%22">Strains & stresses (Mechanics)</searchLink><br /><searchLink fieldCode="DE" term="%22Material+plasticity%22">Material plasticity</searchLink><br /><searchLink fieldCode="DE" term="%22Shear+zones%22">Shear zones</searchLink><br /><searchLink fieldCode="DE" term="%22Metamorphic+rocks%22">Metamorphic rocks</searchLink><br /><searchLink fieldCode="DE" term="%22Chemical+equilibrium%22">Chemical equilibrium</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: • In kågen gabbros, strain is mainly accommodated by dissolution precipitation creep. • Homogenization of reactions is controlled at a scale of ∼100 µm. • Chemical equilibrium is reached locally, residual zoning reflects reaction progress. • Rheological laws should integrate dissolution-precipitation processes. Strain localization within crustal shear zones involves intricate feedback between deformation mechanisms, metamorphic reactions and fluid circulation. Despite evidence that these high-deformation zones proceed at least partly through dissolution-precipitation creep, available creep laws so far only account for dislocation creep and/or solid-state diffusion processes. Deciphering the role and the contribution of dissolution-precipitation creep to strain accommodation is now required to further understand the rheological behavior of polymineralic crustal rocks. This study combines high-resolution microstructural and compositional analytical techniques to track the progressive deformation of the Kågen metagabbros, at and below grain scale. The Kågen metagabbros preserved a strain and re-equilibration gradient over outcrop-scale, where metamorphic re-equilibrations and fluid infiltration took place at constant pressure and temperature representative of lower crustal conditions (ca. 1 GPa - 660 ± 25 °C). The comparison and quantification of chemical and microstructural information in this shear zone, through pixel-per-pixel and grain-per-grain correlated EPMA and EBSD maps, enables tracking grain-scale deformation mechanisms as well as the interplay between grain size reduction, mineral reactions, phase mixing and material transfer. Dissolution-precipitation creep appears dominant for strain accommodation in the Kågen metagabbros shear zone. As deformation progresses, nucleation of new metamorphic minerals (clinopyroxene, plagioclase, amphibole) allow for grain size reduction and compositional homogenization through dissolution, transport and precipitation processes associated with fluid ingression along grain boundaries. Intracrystalline plastic deformation is here insignificant for strain accommodation. Thermodynamic modeling and textural analysis reveal that re-equilibration processes are spatially controlled by microdomains where equilibrium is reached locally, on a scale of ∼100 µm. This study calls for integrating reactions, dissolution-precipitation processes, fluids and polymineralic assemblages into rheological laws for a reliable assessment of the mechanical evolution of metamorphic rocks. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Earth & Planetary Science Letters is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.epsl.2025.119275 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 1 StartPage: N.PAG Subjects: – SubjectFull: Strains & stresses (Mechanics) Type: general – SubjectFull: Material plasticity Type: general – SubjectFull: Shear zones Type: general – SubjectFull: Metamorphic rocks Type: general – SubjectFull: Chemical equilibrium Type: general Titles: – TitleFull: Grain-scale feedback between deformation mechanisms and metamorphic reactions: Dissolution-precipitation processes in the lower crust (Kågen gabbros). Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Mérit, Louise – PersonEntity: Name: NameFull: Soret, Mathieu – PersonEntity: Name: NameFull: Dubacq, Benoît – PersonEntity: Name: NameFull: Agard, Philippe – PersonEntity: Name: NameFull: Précigout, Jacques – PersonEntity: Name: NameFull: Stünitz, Holger IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 04 Text: Apr2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 0012821X Numbering: – Type: volume Value: 656 Titles: – TitleFull: Earth & Planetary Science Letters Type: main |
| ResultId | 1 |
