Conditions for bubble elongation in cold ice-sheet ice

Abstract Highly elongated bubbles are sometimes observed in ice-sheet ice. Elongation is favored by rapid ice deformation, and opposed by diffusive processes. We use simple models to show that vapor transport dominates diffusion except possibly very close to the melting point, and that latent-heat e...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Alley, Richard B., Fitzpatrick, Joan J.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1999
Subjects:
Online Access:http://dx.doi.org/10.1017/s0022143000003129
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000003129
Description
Summary:Abstract Highly elongated bubbles are sometimes observed in ice-sheet ice. Elongation is favored by rapid ice deformation, and opposed by diffusive processes. We use simple models to show that vapor transport dominates diffusion except possibly very close to the melting point, and that latent-heat effects are insignificant. Elongation is favored by larger bubbles at pore close-off, but is nearly independent of bubble compression below close-off. The simple presence of highly elongated bubbles indicates only that a critical ice-strain rate has been exceeded for significant time, and provides no information on possible disruption of stratigraphic continuity by ice deformation.