school energy&environment

Ice-sheets: continental glaciers

Ice-sheets, also known with the Norwegian term, inlandsis, continental ice, are expanse of ice with a surface area of over 50,000 km², where ice buries and masks the underlying relief that does not influence its trend.
The surface is generally mildly convex, like a kind of very flat dome, from which higher peaks of the underlying relief may emerge; these are named nunatak, an Inuit term that means “isolated mountain”. The central, more raised sector, of an ice-sheet is known as the dome.
Ice caps are similar to ice-sheets but their size is smaller.
From the ice-sheets, ice flows  branching off radially in various directions, forming the so called outlet glaciers.   These are veritable rivers of ice, at times their size is immense: the world’s largest glacier is Lambert Glacier that flows from the Antarctic sheet. It is 400 km long and over 50 km wide.
Most outlet glaciers reach the sea where they form snout of ice floating on the sea surface and extend even for many kilometres – through a process called calving most icebergs are formed here. The Lambert Glacier for example, flows into the Amery Ice shelf  forming a floating tongue that extends up to 300 km with a front that is 200 km wide.
Approximately 85.7% of the ice on world’s surface is found in the large ice-sheets of Antarctica, about 10.9% are in the Greenland ice-sheet: these two areas together account for almost the entire amount of the world’s ice (96.6%). Much smaller ice-sheets and ice caps are found in Alaska, on the islands of the Canadian archipelago (Baffin, Ellesmere, Heiberg, Victoria)  and in Iceland, on the Jan Mayen,  Svalbard  and Franz Josef Land archipelagos and on the Scandinavian peninsula (where the most extensive glacier is Jostedalsbre , where bre means glacier, the largest in Europe, excluding Iceland). In the Southern hemisphere, vast extensions of ice, similar to ice-sheets can be found in the Patagonian Andes, forming the Hielo Continental (hielo means chill or ice in Spanish) with a surface area of 17,000 km² and 50 outlet glaciers spreading from it : some of these terminate in large ice contact lakes, like Lake Vidma and Lake Argentino.