19 February 2008

Rock glaciers in Akugdlit (Mellemfjord), Disko Island, West Greenland

Rock glaciers are somewhat like normal glaciers except that they consist of vast amounts of rock with an ice matrix. The ice can either be the remains of glacier ice, snow, or water that has entered the pore space between the rocks and subsequently frozen.

Rock glaciers form where the annual precipitation is too small for normal glaciation to occur, and where there is a large supply of rock debris from steep mountain sides. They are thus found in cold, high relief landscapes. Rock glaciers typically move with a speed of 0.05-1 m/year and thus transport vast amounts of talus away from the rock fall area at the bottom of the mountains. Consequently they are of high importance for landscape development and geomorphology in the areas where they exist.

The largest concentration of rock glaciers is found on Disko Island, West Greenland, where at least 200 rock glaciers have been identified, but they are found in other high relief areas such as the Alps, the mountains of Afghanistan, the US (e.g. Colorado, Alaska, Wyoming), Iceland, Khazakhstan and Svalbard.

For scale, in this picture the top of the mountains stand at approximately 800 meters above sea level. The picture is taken towards the south.

The picture was taken during a 4-week field trip to W-Greenland during the summer between my 3rd and 4th year at university, in 1995. 

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