Structures produced by chemical etching on the basal plane of ice crystals have been studied and are discussed in terms of non-basal glide features. Slip bands, revealed by parallel rows of etch pits, generally result from a rapidly applied stress. Etch channels were observed relatively rarely in these experiments; they can be interpreted as trails of dislocations moving slowly under the action of local stresses, sometimes to stresses produced during the etching process. Features of the

more »

... indicate that the dislocations emerging on the basal plane are screw dislocations; their Burgers vector was considered by previous authors to be in the direction <1123>, gliding on {1122}and {101o} slip planes. This assumption is inconsistent with the changes of channel direction we observed, for which the {0111}and {2421}slip planes would have to be considered. As a simpler hypothesis the glide system 〈0001〉, {101o} and 〈0001〉, {1120}is proposed.