Elastic geobarometry for host-inclusion systems can provide new constraints to assess the pressure and temperature conditions attained during metamorphism. Current experimental approaches and theory are developed only for crystals immersed in a hydrostatic stress field, whereas inclusions experience deviatoric stress. We have developed a method to determine the strains in quartz inclusions from Raman spectroscopy using the concept of the phonon-mode Grüneisen tensor. We used ab initio Hartree-Fock/Density Functional Theory to calculate the wavenumbers of the Raman-active modes as a function of different strain conditions. Least-squares fits of the phonon-wavenumber shifts against strains have been used to obtain the components of the mode Grüneisen tensor of quartz (γm1 and γm3) that can be used to calculate the strains in inclusions directly from the measured Raman shifts. The concept is demonstrated with the example of a natural quartz inclusion in eclogitic garnet from Mir kimberlite and has been validated against direct X-ray diffraction measurement of the strains in the same inclusion.

Murri, M., Mazzucchelli, M., Campomenosi, N., Korsakov, A., Prencipe, M., Mihailova, B., et al. (2018). Raman elastic geobarometry for anisotropic mineral inclusions. AMERICAN MINERALOGIST, 103(11), 1869-1872 [10.2138/am-2018-6625CCBY].

Raman elastic geobarometry for anisotropic mineral inclusions

Murri M.;
2018

Abstract

Elastic geobarometry for host-inclusion systems can provide new constraints to assess the pressure and temperature conditions attained during metamorphism. Current experimental approaches and theory are developed only for crystals immersed in a hydrostatic stress field, whereas inclusions experience deviatoric stress. We have developed a method to determine the strains in quartz inclusions from Raman spectroscopy using the concept of the phonon-mode Grüneisen tensor. We used ab initio Hartree-Fock/Density Functional Theory to calculate the wavenumbers of the Raman-active modes as a function of different strain conditions. Least-squares fits of the phonon-wavenumber shifts against strains have been used to obtain the components of the mode Grüneisen tensor of quartz (γm1 and γm3) that can be used to calculate the strains in inclusions directly from the measured Raman shifts. The concept is demonstrated with the example of a natural quartz inclusion in eclogitic garnet from Mir kimberlite and has been validated against direct X-ray diffraction measurement of the strains in the same inclusion.
Articolo in rivista - Articolo scientifico
Deviatoric stress; elastic anisotropy; elastic barometry; metamorphic rocks; mineral inclusions; quartz in garnet
English
2018
103
11
1869
1872
none
Murri, M., Mazzucchelli, M., Campomenosi, N., Korsakov, A., Prencipe, M., Mihailova, B., et al. (2018). Raman elastic geobarometry for anisotropic mineral inclusions. AMERICAN MINERALOGIST, 103(11), 1869-1872 [10.2138/am-2018-6625CCBY].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/274424
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