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Crystallographic preferred orientations of exhumed subduction channel rocks from the Eclogite Zone of the Tauern Window (Eastern Alps, Austria), and implications on rock elastic anisotropies at great depths
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SYSNO ASEP 0444374 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Crystallographic preferred orientations of exhumed subduction channel rocks from the Eclogite Zone of the Tauern Window (Eastern Alps, Austria), and implications on rock elastic anisotropies at great depths Author(s) Keppler, R. (DE)
Ullemeyer, K. (DE)
Behrmann, J. H. (DE)
Stipp, M. (DE)
Kurzawski, R. M. (DE)
Lokajíček, Tomáš (GLU-S) RID, SAI, ORCIDSource Title Tectonophysics. - : Elsevier - ISSN 0040-1951
647/648, April (2015), s. 89-104Number of pages 16 s. Publication form Print - P Language eng - English Country NL - Netherlands Keywords crystallographic preferred orientation ; eclogite Zone ; elastic properties ; P-wave anisotropy ; retrogression of eclogites ; subduction channel Subject RIV DC - Siesmology, Volcanology, Earth Structure Institutional support GLU-S - RVO:67985831 UT WOS 000353087400007 EID SCOPUS 84925940452 DOI 10.1016/j.tecto.2015.02.011 Annotation Crystallographic preferred orientations (CPO) of rocks from an exhumed subduction channel of the Alpine orogen were determined using time-of-flight neutron diffraction. This method allows the investigation of large polymineralic samples and, more importantly, the application of full pattern fit methods to constrain CPOs of mineralogically complex rocks. Samples studied include intensely deformed fresh and retrogressed eclogites, as well as metasediments, which are interleaved with the eclogites in the subduction channel. From the CPO, seismic properties of the samples were calculated. P-wave anisotropies of the eclogite samples are fairly low, with an average of about 1.5%, and mainly constrained by pronounced omphacite CPO. Growth and deformation of retrograde amphibole in the eclogites also led to a pronounced CPO, which has a large impact on seismic anisotropies by raising them to up to 3.7% and changing the orientations of velocity maxima. Elastic anisotropies of the subducted metasediments are higher (up to 7.4%) and constrained by quartz and mica CPO in clastics and by calcite CPO in marble. V-P/V-S ratios may help to distinguish fresh eclogites from retrogressed ones, and both rock types from mantle peridotites of downgoing lithospheric slabs in seismic imaging. Our data also indicate that subducted terrigenous sediments not only are strongly anisotropic, but also have low V-P/V-S ratios. This way there may be the potential to image them by seismic tomography at depth in active subduction channels. Workplace Institute of Geology Contact Jana Popelková, popelkova@gli.cas.cz, Sabina Janíčková, Tel.: 233 087 272 Year of Publishing 2016
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