par Samyn, Denis 
;Fitzsimons, Sean;Lorrain, Reginald
Référence International journal of earth sciences
Publication Publié, 2009
;Fitzsimons, Sean;Lorrain, Reginald Référence International journal of earth sciences
Publication Publié, 2009
Article révisé par les pairs
| Résumé : | Structural analyses were conducted in the basal zone of an Antarctic glacier. The studied basal ice sequence was retrieved from a 20-m-long subglacial tunnel dug at the margin of the glacier and is at the temperature of -17°C. For the first time, rotating clast systems embedded within debris-rich ice were thin-sectioned using specially designed cutting techniques. The observed structures reflect the occurrence of pervasive shearing at the base of the glacier, and can be used as shear sense indicators. In addition, some of these structures provide evidence for the presence of thin liquid films at the time of formation despite the marked freezing temperature of the ice. It is showed here that cautious analysis of deformation structures present in debris-bearing ice may bring insights not only into the flow dynamics of the embedding matrix, but also into the behaviour of the interstitial fluid network at the base of cold glaciers and ice sheets. © 2009 Springer-Verlag. |
