Water redistribution in experimentally deformed natural milky quartz single crystals-Implications for H 2 O-weakening processes

Autor: Stünitz, Holger, Thust, A., Heilbronner, R., Behrens, H., Kilian, R., Tarantola, A., Fitz Gerald, J. D.
Přispěvatelé: Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Department of Geology, University of Tromsø, University of Tromsø (UiT), Géodynamique - UMR7327, Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Institut für Geowissenschaften [Frankfurt am Main], Goethe-Universität Frankfurt am Main, University of Basel (Unibas), Department of Environmental Sciences [Basel], Institute for Mineralogy, Leibniz University of Hannover, Leibniz Universität Hannover [Hannover] (LUH), GeoRessources, Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Institut national des sciences de l'Univers (INSU - CNRS), Research School of Earth Sciences [Canberra] (RSES), Australian National University (ANU), NF project NF200020.119878
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Journal of Geophysical Research : Solid Earth
Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2017, 122, pp.866-894. ⟨10.1002/2016JB013533⟩
Journal of geophysical research / Solid earth 122(2), 866-894 (2017). doi:10.1002/2016JB013533
ISSN: 2169-9313
2169-9356
Popis: International audience; Natural quartz single crystals were experimentally deformed in two orientations: (1) ⊥ to one prism plane and (2) in O + orientation at 900 and 1000°C, 1.0 and 1.5 GPa, and strain rates of ~1 × 10 À6 s À1. In addition, hydrostatic and annealing experiments were performed. The starting material was milky quartz, which consisted of dry quartz with a large number of fluid inclusions of variable size up to several 100 μm. During pressurization fluid inclusions decrepitated producing much smaller fluid inclusions. Deformation on the sample scale is anisotropic due to dislocation glide on selected slip systems and inhomogeneous due to an inhomogeneous distribution of fluid inclusions. Dislocation glide is accompanied by minor dynamic recovery. Strongly deformed regions show a pointed broad absorption band in the ~3400 cm À1 region consisting of a superposition of bands of molecular H 2 O and three discrete absorption bands (at 3367, 3400, and 3434 cm À1). In addition, there is a discrete absorption band at 3585 cm À1 , which only occurs in deformed regions and reduces or disappears after annealing, so that this band appears to be associated with dislocations. H 2 O weakening in inclusion-bearing natural quartz crystals is assigned to the H 2 O-assisted dislocation generation and multiplication. Processes in these crystals represent recycling of H 2 O between fluid inclusions, cracking and crack healing, incorporation of structurally bound H in dislocations, release of H 2 O from dislocations during recovery, and dislocation generation at very small fluid inclusions. The H 2 O weakening by this process is of disequilibrium nature because it depends on the amount of H 2 O available.
Databáze: OpenAIRE
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