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dc.contributor.authorPongrac, Petar
dc.contributor.authorJeřábek, Petr
dc.contributor.authorStunitz, Holger
dc.contributor.authorRaimbourg, Hugues
dc.contributor.authorHeilbronner, Renee
dc.contributor.authorRacek, Martin
dc.contributor.authorNègre, Lucille
dc.date.accessioned2022-11-29T10:14:36Z
dc.date.available2022-11-29T10:14:36Z
dc.date.issued2022-05-21
dc.description.abstractNatural quartzite samples, as-is and with 0.1 wt% of added H<sub>2</sub>O, have been deformed up to ∼30% bulk strain in axial shortening experiments with constant strain rate of ∼10<sup>−6</sup> s<sup>−1</sup> at 900 °C and 1 GPa, and in strain rate stepping ∼10<sup>−5</sup> to ∼10<sup>−7</sup> s<sup>−1</sup> at 900 °C and 1–1.5 GPa, in order to investigate the role of H<sub>2</sub>O in deformation and recrystallization of quartz. H2O-added samples showed ∼30 MPa lower mean strengths than as-is samples. Samples weaken slightly after 15% strain with mean flow stresses in the range of 154–227 MPa, and stress exponent (n) values between 1.45 and 2.13. The original quartz grains have been deformed plastically (dislocation glide). Discrete mode I cracks without detectable offset have developed in addition to plastic strain. Deformation was associated with recrystallization of up to 20% of the material in the most deformed parts of the samples. New grains were nucleated by both cracking and subgrain rotation, and were largely reconstituted by H<sub>2</sub>O-promoted grain boundary migration, related to dissolution-precipitation processes. This reconstitution of material is documented by a change in luminescence to blue, caused by trace elements exchange in quartz structure. The blue luminescence is prominent along healed cracks and high angle grain boundaries while it was not observed along the low angle boundaries formed by subgrain rotation. Compared to the as-is samples, the crack-related recrystallization is more frequent in the H<sub>2</sub>O-added samples. The low stress exponent values may indicate dissolution-precipitation and grain boundary sliding processes to accommodate incompatibilities at grain boundaries arising from an insufficient number of active slip systems. We suggest that the ubiquitous presence of H<sub>2</sub>O in nature may promote recrystallization of quartz by combinations of cracking, dislocation glide and creep and dissolution-precipitation processes.en_US
dc.identifier.citationPongrac P, Jeřábek P, Stunitz H, Raimbourg H, Heilbronner RS, Racek M, Nègre L. Mechanical properties and recrystallization of quartz in presence of H<inf>2</inf>O: Combination of cracking, subgrain rotation and dissolution-precipitation processes. Journal of Structural Geology. 2022;160en_US
dc.identifier.cristinIDFRIDAID 2030740
dc.identifier.doi10.1016/j.jsg.2022.104630
dc.identifier.issn0191-8141
dc.identifier.issn1873-1201
dc.identifier.urihttps://hdl.handle.net/10037/27585
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalJournal of Structural Geology
dc.relation.projectIDAndre: Charles University (GAUK 488119)en_US
dc.relation.projectIDAndre: Center for Geosphere Dynamics (UNCE/SCI/006)en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2022 The Author(s)en_US
dc.titleMechanical properties and recrystallization of quartz in presence of H<inf>2</inf>O: Combination of cracking, subgrain rotation and dissolution-precipitation processesen_US
dc.type.versionacceptedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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