Ab initio calculations of elastic constants of plagioclase feldspars

Plagioclase feldspars comprise a large portion of the Earth's crust and are very anisotropic, making accurate knowledge of their elastic properties important for understanding the crust's anisotropic seismic signature. However, except for albite, existing elastic constants for plagioclase...

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Bibliographic Details
Published inThe American mineralogist Vol. 99; no. 11-12; pp. 2344 - 2352
Main Authors Kaercher, Pamela, Militzer, Burkhard, Wenk, Hans-Rudolf
Format Journal Article
LanguageEnglish
Published Washington Mineralogical Society of America 01.11.2014
Walter de Gruyter GmbH
Subjects
ab initio calculations
andesine
Anisotropy
anorthite
body waves
crust
crystal systems
elastic constants
Elastic properties
elastic waves
feldspar group
framework silicates
Knowledge
labradorite
Measurement
Mineralogy
numerical models
P-waves
plagioclase
Plagioclase feldspars
propagation
S-waves
seismic anisotropy
seismic waves
silicates
Symmetry
triclinic system
velocity
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Summary:Plagioclase feldspars comprise a large portion of the Earth's crust and are very anisotropic, making accurate knowledge of their elastic properties important for understanding the crust's anisotropic seismic signature. However, except for albite, existing elastic constants for plagioclase feldspars are derived from measurements that cannot resolve the triclinic symmetry. We calculate elastic constants for plagioclase end-members albite NaAlSi3O8 and anorthite CaAl2Si2O8 and intermediate andesine/labradorite NaCaAl3Si5O16 using density functional theory to compare with and improve existing elastic constants and to study trends in elasticity with changing composition. We obtain elastic constants similar to measured elastic constants and find that anisotropy decreases with anorthite content.
ISSN:0003-004X
1945-3027
DOI:10.2138/am-2014-4796