| type de publication : |
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Articles dans des revues avec comité de lecture |
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| domaine : |
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Planète et Univers/Sciences de la Terre/Géomorphologie
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| titre : |
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Competition between grain growth and grain-size reduction in polar ice |
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| auteur(s) : |
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J. Roessiger 1, P. D. Bons 1, A. Griera 2, M. W. Jessell ( ) 3, L. Evans 4, M. Montagnat 5, S. Kipfstuhl 6, S. Faria 7, I. Weikusat 6 |
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| laboratoire : |
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| Équipe de recherche : |
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EDGE |
| résumé : |
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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. |
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langue du texte
intégral : |
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Anglais |
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| journal : |
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Journal of Glaciology |
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| Audience : |
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internationale |
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| date de publication : |
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01/10/2011 |
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| volume : |
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57 |
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| numéro : |
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205 |
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| page, identifiant, ... : |
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942-948 |
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| contrat, financement : |
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German Research Foundation (DFG) project BO-1776/7 |
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