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dc.contributor.authorMcNamara, David D.
dc.contributor.authorWheeler, J.
dc.contributor.authorPearce, M.
dc.contributor.authorPrior, D.J.
dc.date.accessioned2017-08-14T12:58:56Z
dc.date.available2017-08-14T12:58:56Z
dc.date.issued2012-09-12
dc.identifier.citationMcNamara, D. D., Wheeler, J., Pearce, M., & Prior, D. J. (2012). Fabrics produced mimetically during static metamorphism in retrogressed eclogites from the Zermatt-Saas zone, Western Italian Alps. Journal of Structural Geology, 44, 167-178. doi: http://dx.doi.org/10.1016/j.jsg.2012.08.006en_IE
dc.identifier.issn0191-8141
dc.identifier.issn1873-1201
dc.identifier.urihttp://hdl.handle.net/10379/6721
dc.description.abstractLattice preferred orientations (LPOs) are commonly interpreted to form by dislocation creep. Consequently they are used to infer deformation at the metamorphic grade at which the minerals were stable, especially if those minerals show a shape fabric. Here we show that LPOs can occur through mimicry of a pre-existing LPO, so they formed statically, not during deformation. Omphacite and glaucophane LPOs occur in eclogite facies rocks from the Zermatt-Saas Unit of the Northwest Italian Alps. Barroisite grew during greenschist facies retrogression and has an LPO controlled significantly by the eclogite fades omphacite and glaucophane LPOs, rather than directly by deformation. Using spatially resolved lattice orientation data from the three key minerals, collected using electron backscatter diffraction, we deploy a new technique of interphase misorientation distribution analysis to prove this. Barroisite LPO develops by mimicry of omphacite (via a particular lattice orientation relationship) and by direct topotactic and epitactic replacement of glaucophane. LPO in turn influenced anisotropic grain growth, resulting in a barroisite grain shape fabric. Thus regional retrogression during exhumation of the Zermatt-Saas high-pressure rocks was, in large part, static, rather than dynamic as previously interpreted. In general the possibility of mimetic fabrics forming during metamorphic reactions must be borne in mind when interpreting direct structural observations and seismic anisotropy data in terms of deformation, in both crust and mantle. (C) 2012 Elsevier Ltd. All rights reserved.en_IE
dc.formatapplication/pdfen_IE
dc.language.isoenen_IE
dc.publisherElsevieren_IE
dc.relation.ispartofJournal Of Structural Geologyen
dc.subjectLattice preferred orientationen_IE
dc.subjectLago di cignanaen_IE
dc.subjectElectron backscatter diffractionen_IE
dc.subjectOceanic crusten_IE
dc.subjectDeformationen_IE
dc.subjectMechanismsen_IE
dc.subjectOmphaciteen_IE
dc.subjectProgradeen_IE
dc.subjectRecrystallizationen_IE
dc.subjectHigh pressure metamorphismen_IE
dc.subjectInterphase misorientation distributionen_IE
dc.subjectMimeticen_IE
dc.subjectEclogiteen_IE
dc.subjectAlpsen_IE
dc.titleFabrics produced mimetically during static metamorphism in retrogressed eclogites from the Zermatt-Saas zone, Western Italian Alpsen_IE
dc.typeArticleen_IE
dc.date.updated2017-07-22T14:11:56Z
dc.identifier.doi10.1016/j.jsg.2012.08.006
dc.local.publishedsourcehttps://doi.org/10.1016/j.jsg.2012.08.006en_IE
dc.description.peer-reviewedpeer-reviewed
dc.contributor.funder|~|
dc.internal.rssid11991942
dc.local.contactDavid Mcnamara, -. - Email: david.d.mcnamara@nuigalway.ie
dc.local.copyrightcheckedYes
dc.local.versionACCEPTED
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