At http://wattsupwiththat.com/2013/12/03/a-new-look-at-greenlands-ice-sheet… … I suppose the impetus for this article comes from climate change – is the ice melting in Greenland, can it happen rapidly, and what is the scare factor on the CAGW measurement meter. We have had several SIS articles on this subject where it is equally a matter of speculation that ice sheets come and go more quickly than mainstream allows.
Scientists are interested in how the topography of the land below the ice sheet affects ice movements. NASA has been monitoring the Antarctic and the Arctic for a few years (and the emphasis is on a few years) recording ice sheet elevation changes (is it growing or is it shrinking) using satellites. Radar instruments can also look at the landscape beneath the ice sheets and there is an image showing a surprisng finding – the bedrock is jagged rather than smoothed. See also www.nasa.gov/icebridge
There is also a topographic map of Greenland at http://upload.wikimedia.org/wikipedia/commons/8/8b/Topographic_map_of_Gr…
One of the commenters, at 4.50am, looking at the image, wonders what might have happened at roughly 2000m thickness of the ice core/ice sheet, a major dark horizon. He asks if it was volcanic.