The Ice Cap
Greenland’s inland ice is the largest ice cap in the world outside the Antarctic. Between the two of them, these two ice caps contain more than 99 percent of the world’s glacier ice.
The Land below the Ice
The ice cap consists of snow which is compressed into glacier ice as new snow falls on top of the old. At the same time the ice expands towards the sides of the ice cover, where it calves into the sea. In the eastern and southern parts of Greenland, the ice cap is delimited by large mountain ranges. For this reason its central parts are primarily drained towards the west, especially into the Disko Bay.
Calving ice from the inland ice is concentrated in a few large debouchment glaciers. To a great extent these follow the troughs which were eroded in the underground by rivers and earlier glacier movements.
Cross section of Greenland’s ice cap from east to west (Figure: GEUS).
Sermeq Kujalleq in the bottom of the Ilulissat Icefjord is an example of a debouchment glacier. Its high speed and productivity is caused by the fact that ice from a very large drainage area is concentrated in a small stream which follows a deep underground trough.
Read more about the inland ice and the glaciology of Ilulissat Icefjord on the website of the Geological Survey of Denmark and Greenland (GEUS).