1 year agoNovember 10, 2012
We describe a sequence of supraglacial lakes on the George VI Ice Shelf, Antarctica, that migrate along the boundary of the ice shelf with Alexander Island in the manner of a traveling wave, with a velocity that differs from the local ice-shelf flow in both magnitude and direction. These lakes are arranged en échelon along a grounding line of the ice shelf where the flow displays the atypical feature of being directed toward land. A simple model presented here suggests that the propagating lakes form in the depressions of a viscous-buckling wave associated with compressive ice-shelf stresses and ice-flow directed obliquely toward the coastline. The existence of these lakes and their propagation gives rise to the implication that other ice-shelf surface features (e.g., patterns of swells and depressions, surface lakes, and drainage) can be organized by large-scale viscous buckling behavior, when ice-shelf flow is strongly compressive.