Large, continental bodies of ice (ice sheets, i.e. Antarctica, Greenland) and small, local bodies of ice (ice caps, i.e. Vatnajokull, Jostedalsbreen) are normally subdivided into ice domes (high areas of relatively slow-moving ice), and ice streams and outlet glaciers (areas with more rapidly flowing ice). An ice sheet covers a large area, and the major part has such a thickness that the subglacial topography is not reflected on the ice-sheet surface. Ice sheets and ice caps are of sufficient thickness to submerge the underlying landscape. Around the margins of ice sheets and ice caps, however, fast-moving ice streams and outlet glaciers are located in valleys and fjords. An area of more than 50,000 km is commonly used for defining ice sheets. Therefore, the ice masses that at present cover Antarctica and Greenland and the former ice masses over Scandinavia, North America, the British Isles, the Barents Sea Shelf and northern Siberia are ice sheets, whereas ice masses over Svalbard, Ellesmere Island, Baffin Island and Iceland are designated as ice caps.
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