Competition between grain growth and grain-size reduction in polar ice

Abstract : Static (or 'normal') grain growth, i.e. grain boundary migration driven solely by grain boundary energy, is considered to be an important process in polar ice. Many ice-core studies report a continual increase in average grain size with depth in the upper hundreds of metres of ice sheets, while at deeper levels grain size appears to reach a steady state as a consequence of a balance between grain growth and grain-size reduction by dynamic recrystallization. The growth factor k in the normal grain growth law is important for any process where grain growth plays a role, and it is normally assumed to be a temperature-dependent material property. Here we show, using numerical simulations with the program Elle, that the factor k also incorporates the effect of the microstructure on grain growth. For example, a change in grain-size distribution from normal to log-normal in a thin section is found to correspond to an increase in k by a factor of 3.5.
Type de document :
Article dans une revue
Journal of Glaciology, International Glaciological Society, 2011, 57 (205), pp.942-948. <10.3189/002214311798043690>


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Contributeur : Pascale Talour <>
Soumis le : vendredi 2 décembre 2011 - 09:34:48
Dernière modification le : jeudi 12 mars 2015 - 16:57:42

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J. Roessiger, P. D. Bons, A. Griera, M. W. Jessell, L. Evans, et al.. Competition between grain growth and grain-size reduction in polar ice. Journal of Glaciology, International Glaciological Society, 2011, 57 (205), pp.942-948. <10.3189/002214311798043690>. <insu-00647437>

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