Hide metadata

dc.date.accessioned2020-09-30T18:26:21Z
dc.date.available2020-09-30T18:26:21Z
dc.date.created2020-09-28T15:06:33Z
dc.date.issued2020
dc.identifier.citationKiraly, Agnes Conrad, Clinton Phillips Hansen, Lars N. . Evolving viscous anisotropy in the upper mantle and its geodynamic implications. Geochemistry Geophysics Geosystems. 2020, 21
dc.identifier.urihttp://hdl.handle.net/10852/80181
dc.description.abstractAsthenospheric shear causes some minerals, particularly olivine, to develop anisotropic textures that can be detected seismically. In laboratory experiments, these textures are also associated with anisotropic viscous behavior, which should be important for geodynamic processes. To examine the role of anisotropic viscosity for asthenospheric deformation, we developed a numerical model of coupled anisotropic texture development and anisotropic viscosity, both calibrated with laboratory measurements of olivine aggregates. This model characterizes the time‐dependent coupling between large‐scale formation of lattice‐preferred orientation (i.e., texture) and changes in asthenospheric viscosity for a series of simple deformation paths that represent upper mantle geodynamic processes. We find that texture development beneath a moving surface plate tends to align the a axes of olivine into the plate motion direction, which weakens the effective viscosity in this direction and increases plate velocity for a given driving force. Our models indicate that the effective viscosity increases for shear in the horizontal direction perpendicular to the a axes. This increase should slow plate motions and new texture development in this perpendicular direction and could impede changes to the plate motion direction for tens of millions of years. However, the same well‐developed asthenospheric texture may foster subduction initiation perpendicular to the plate motion and deformations related to transform faults, as shearing on vertical planes seems to be favored across a sublithospheric olivine texture. These end‐member cases examining shear deformation in the presence of a well‐formed asthenospheric texture illustrate the importance of the mean olivine orientation, and its associated viscous anisotropy, for a variety of geodynamic processes.
dc.languageEN
dc.publisherThe Geochemical Society
dc.rightsAttribution 4.0 International
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.titleEvolving viscous anisotropy in the upper mantle and its geodynamic implications
dc.typeJournal article
dc.creator.authorKiraly, Agnes
dc.creator.authorConrad, Clinton Phillips
dc.creator.authorHansen, Lars N.
cristin.unitcode185,15,22,40
cristin.unitnameSenter for Jordens utvikling og dynamikk
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.qualitycode2
dc.identifier.cristin1834367
dc.identifier.bibliographiccitationinfo:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Geochemistry Geophysics Geosystems&rft.volume=21&rft.spage=&rft.date=2020
dc.identifier.jtitleGeochemistry Geophysics Geosystems
dc.identifier.volume21
dc.identifier.issue10
dc.identifier.pagecount22
dc.identifier.doihttps://doi.org/10.1029/2020GC009159
dc.identifier.urnURN:NBN:no-83272
dc.type.documentTidsskriftartikkel
dc.type.peerreviewedPeer reviewed
dc.source.issn1525-2027
dc.identifier.fulltextFulltext https://www.duo.uio.no/bitstream/handle/10852/80181/2/2020GC009159.pdf
dc.type.versionPublishedVersion
cristin.articleide2020GC009
dc.relation.projectNFR/223272


Files in this item

Appears in the following Collection

Hide metadata

Attribution 4.0 International
This item's license is: Attribution 4.0 International