Show simple item record

dc.contributor.authorTasaka, Miki
dc.contributor.authorZimmerman, Mark E
dc.contributor.authorKohlstedt, David L.
dc.contributor.authorStünitz, Holger
dc.contributor.authorHeilbronner, Renée
dc.date.accessioned2018-08-16T11:38:41Z
dc.date.available2018-08-16T11:38:41Z
dc.date.issued2017-09-08
dc.description.abstractTo understand the processes involved in phase mixing during deformation and the resulting changes in rheological behavior, we conducted torsion experiments on samples of iron‐rich olivine plus orthopyroxene. The experiments were conducted at a temperature, T, of 1200°C and a confining pressure, P, of 300 MPa using a gas‐medium deformation apparatus. Samples composed of olivine plus 26% orthopyroxene were deformed to outer radius shear strains up to γ ≈ 26. In samples deformed to lower strains of γ ≲ 4, elongated olivine and pyroxene grains form a compositional layering. Already by this strain, mixtures of small equant grains of olivine and pyroxene begin to develop and continue to evolve with increasing strain. The ratios of olivine to pyroxene grain size in deformed samples follow the Zener relationship, indicating that pyroxene grains effectively pin the grain boundaries of olivine and inhibit grain growth. Due to the reduction in grain size, the dominant deformation mechanism changes as a function of strain. The microstructural development forming more thoroughly mixed, fine‐grained olivine‐pyroxene aggregates can be explained by the difference in diffusivity among Me (Fe or Mg), O, and Si, with transport of MeO significantly faster than that of SiO2. These mechanical and associated microstructural properties provide important constraints for understanding rheological weakening and strain localization in upper mantle rocks.en_US
dc.description.sponsorshipJSPS Research Fellowship for Young Scientists The Japan Society for the Promotion of Science NASA grant NSF granten_US
dc.descriptionAn edited version of this paper was published by AGU. Copyright (2017) American Geophysical Union. Source at <a href=https://doi.org/10.1002/2017JB014333> https://doi.org/10.1002/2017JB014333</a>.en_US
dc.identifier.citationTasaka, M., Zimmerman, M.E., Kohlstedt, D.L., Stünitz, H. & Heilbronner, R. (2017). Rheological Weakening of Olivine + Orthopyroxene Aggregates Due To Phase Mixing: Part 2. Microstructural Development. Journal of Geophysical Research - Biogeosciences, 122(10), 7597-7612. https://doi.org/10.1002/2017JB014333en_US
dc.identifier.cristinIDFRIDAID 1543249
dc.identifier.doi10.1002/2017JB014311
dc.identifier.issn2169-8953
dc.identifier.issn2169-8961
dc.identifier.urihttps://hdl.handle.net/10037/13441
dc.language.isoengen_US
dc.publisherAmerican Geophysical Union (AGU)en_US
dc.relation.journalJournal of Geophysical Research - Biogeosciences
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450en_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450en_US
dc.subjectdeformationen_US
dc.subjectolivineen_US
dc.subjectpyroxeneen_US
dc.subjectZener pinningen_US
dc.subjectphase mixingen_US
dc.titleRheological Weakening of Olivine + Orthopyroxene Aggregates Due To Phase Mixing: Part 2. Microstructural Developmenten_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


File(s) in this item

Thumbnail

This item appears in the following collection(s)

Show simple item record