Compressive creep of ice containing a liquid intergranular phase: rate-controlling processes in the dislocation creep regime

Experiments have been conducted to investigate the effect of melt on the creep behavior of polycrystalline ice deformed in the dislocation creep regime. The transition between a mode with a stress exponent n = 3 and a made with n < 2 is observed for both melt-free and melt-added ice samples. The large influence of the melt phase is not related to the wetting characteristics of the liquid. Owing to the large plastic anisotropy of the ice crystal, the liquid phase would attenuate the internal stress field which develops during the primary creep. The contribution to the deformation of the basal slip (the weaker slip system) would increase with the melt content.