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Infrared spectra of synthetic almandine–grossular and almandine–pyrope garnet solid solutions: evidence for equivalent site behaviour

Published online by Cambridge University Press:  05 July 2018

C. A. Geiger ,
B. Winkler  and
K. Langer
C. A. Geiger
Affiliation:
Institut für Mineralogie und Kristallographie, Technische Universität Berlin, Ernst Reuter-Platz 1, D-1000 Berlin 12, Germany
B. Winkler
Affiliation:
Institut für Mineralogie und Kristallographie, Technische Universität Berlin, Ernst Reuter-Platz 1, D-1000 Berlin 12, Germany
K. Langer
Affiliation:
Institut für Mineralogie und Kristallographie, Technische Universität Berlin, Ernst Reuter-Platz 1, D-1000 Berlin 12, Germany
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Abstract

The infrared (IR) spectra of almandine-grossular and almandine-pyrope garnet solid solutions have been measured using the powder method. Frequency shifts of a band related to internal vibrations associated with the 8-co-ordinate dodecahedral site are nonlinear in almandine-grossular garnets and mimic the form of its molar volume of mixing curve. Almandine-pyrope solid solutions have nearly ideal molar volumes of mixing and the frequency shift of this same 8-co-ordinate site-related band is linear. The IR data support the empirically based crystal chemical model of Equivalent Site (ES) behaviour (Newton and Wood, 1980). The IR spectra give no indication of long-range ordering between Ca and Fe2+ in garnet, but thermodynamic calculations involving Ca-poor garnets might be affected by small volume or short-range ordering anomalies.

Keywords

equivalent site behavioursynthetic garnetsinfrared spectroscopymolar volumes of mixing
Type
Research Article
Information
Mineralogical Magazine , Volume 53 , Issue 370 , April 1989 , pp. 231 - 237
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1989

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References

Burns, R. G. and Huggins, F. E. (1972) Cation determinative curves for Mg-Fe-Mn olivines from vibrational spectra. Am. Mineral. 57, 967-85.Google Scholar
Cressey, G. (1981) Entropies and enthalpies of aluminosilicate garnets. Contrib. Mineral. Petrol. 76, 413-9.CrossRefGoogle Scholar
Cressey, G., Schimd, R. and Wood, B. J. (1978) Thermodynamic properties of almandine-grossular solid solutions. Ibid. 67, 397-404.CrossRefGoogle Scholar
Delany, J. M. (1981) A spectral and thermodynamic investigation of synthetic pyrope-grossular garnets. Unpub. Ph.D. thesis, Univ. Cal. Los Angeles.Google Scholar
Dempsey, M. J. (1980) Evidence for structural changes in garnet caused by calcium substitution. Contrib. Mineral. Petrol. 71, 281-2.CrossRefGoogle Scholar
Geiger, C. A. (1986) Thermodynamic mixing properties of almandine garnet solid solutions. Unpub. Ph.D. thesis, Univ. Chicago.Google Scholar
Geiger, C. A., Newton, R. C. and Kleppa, O. J. (1987) Enthalpy of mixing of synthetic almandine-grossular and almandine-pyrope garnets from high-temperature solution calorimetry. Geochim. Cosmochim. Acta 51, 1755-63.CrossRefGoogle Scholar
Haselton, H. T. and Newton, R. C. (1980) Thermodynamics of pyrope-grossular garnets and their stabilities at high temperatures and high pressures. J. Geophys. Res. 85, 6973-82.CrossRefGoogle Scholar
Iiyama, J. T. (1974) Substitution déformation locale de la maille et équilibre de distribution des éléments en traces entre silicates et solution hydrothermale. Bull. Soc. Fr. Mineral. Cristallogr. 97, 143-51.Google Scholar
Iiyama, J. T. and Volfinger, M. (1976) A model for trace-element distribution in silicate structures. Mineral. Mag. 40, 555-64.CrossRefGoogle Scholar
Kieffer, S. W. (1979) Thermodynamics and lattice vibrations of minerals: 1. Mineral heat capacities and their relationships to simple lattice vibrational models. Rev. Geophys. Space Phys. 17, 1-19.CrossRefGoogle Scholar
Moore, R. K., White, W. B. and Long, T. V. (1971) Vibrational spectra of the common silicates: 1. The garnet. Am. Mineral. 56, 54-71.Google Scholar
Newton, R. C. and Wood, B. J. (1980) Volume behavior of silicate solid solutions. Ibid. 65, 733-45.Google Scholar
Novak, G. A. and Gibbs, G, V. (1971) The crystal chemistry of the silicate garnets. Ibid. 56, 791-825.Google Scholar
O'Neill, H. St. C. and Navrotsky, A. (1984) Cation distribution and thermodynamic properties of binary spinel solid solutions. Ibid. 69, 733-53.Google Scholar
Perkins, D. III (1979) Application of new thermodynamic data to mineral equilibria. Unpub. Ph.D. thesis, Univ. Michigan.Google Scholar
Powell, R. (1987) Darken's quadratic formalism and the thermodynamics of minerals. Am. Mineral. 72, 1-11.Google Scholar
Tarte, P. (1965) Experimental study and interpretation of infrared spectra of silicates and germanates. Mere. Acad. R. Belg. Sci. 8° 35, 4a–b.Google Scholar