Blog Archive

Friday, April 27, 2012

"Traveling supraglacial lakes on George VI Ice Shelf, Antarctica," by C. H. LaBarbera & D. R. MacAyeal, GRL 38 (2011); doi:10.1029/2011GL049970

Geophysical Research Letters 38 (2011) L24501; doi:10.1029/2011GL049970

Traveling supraglacial lakes on George VI Ice Shelf, Antarctica
C. H. LaBarbera (Department of Geology, Cornell College, Mount Vernon, Iowa, USA) and D. R. MacAyeal (Department of Geophysical Sciences, University of Chicago, Chicago, Illinois, USA)


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. 

Received 11 October 2011; accepted 17 November 2011; published 28 December 2011.

Key points:
  • We discover a type of supraglacial lake that propagates as a wave
  • These waves result from large-scale stress regime
  • Thus, large-scale stress regime may determine how lakes mediate shelf stability

Citation: LaBarbera, C. H. and D. R. MacAyeal. (2011). Traveling supraglacial lakes on George VI Ice Shelf, Antarctica, Geophys. Res. Lett., 38, L24501, doi:10.1029/2011GL049970.                                                          

No comments: