A dome-shaped mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometers (12 million acres) (e.g., the Greenland and Antarctic ice sheets).
A thick, subcontinental to continental-scale accumulation of glacier ice and perennial snow that spreads from a center of accumulation, typically in all directions. Also called a Continental Glacier.
An ice body that covers an area of continental size, generally defined as covering 50 000 km2 or more. Currently there are only two ice sheets, the Greenland Ice Sheet and the Antarctic Ice Sheet. The
latter is sometimes subdivided into the East Antarctic Ice Sheet and the West Antarctic Ice Sheet. See ice cap.
A mass of land ice of continental size that is sufficiently thick to cover most of the underlying bed, so that its shape is mainly determined by its dynamics (the flow of the ice as it deforms interna
lly and/or slides at its base). An ice sheet flows outward from a high central ice plateau with a small average surface slope. The margins usually slope more steeply, and most ice is discharged through fast flowing ice streams or outlet glaciers, in some cases into the sea or into ice shelves floating on the sea. There are only two ice sheets in the modern world, one on Greenland and one on Antarctica. During glacial periods there were others.
A mass of ice and snow of considerable thickness and large area. Ice sheets may be resting on rock (see Inland ice sheet) or floating (see Ice shelf). Ice sheets of less than about 50,000 square km re
sting on rock are called ice caps.
A dome-shaped glacier covering an area greater than 50,000 square kilometers. Greenland and Antarctica are considered ice sheets. During the glacial advances of the Pleistocene ice sheets covered larg
e areas of North America, Europe, and Asia. Larger than an ice cap.
A mass of Ice and Snow of considerable thickness and large area. Ice Sheets may be resting on rock or floating. Ice Sheets of less than about 50,000 square km resting on rock are called Ice Caps.
An ice mass which 1) is attached to the coast 2) at least 2 meters in thickness 3) forms where a glacier or ice mass flows down to a coastline and onto the ocean surface and 4) grows by annual snow ac
cumulation or by the seaward extension of land glaciers.
A floating ice sheet of considerable thickness attached to a coast. Ice shelves are usually of great horizontal extent and have a level or gently undulating surface. They are nourished by the accumula
tion of snow and often by the seaward extension of land glaciers. Limited areas may be aground. The seaward edge is termed an ice front (q.v.).
A floating ice sheet of considerable thickness showing 6 to 165 ft (2-50 m) or more above sea level, attached to the coast. Usually of great horizontal extent and with a level or gently undulating sur
face. Nourished by annual snow accumulation and also by the seaward extension of land glaciers. Limited areas may be aground. The seaward edge is termed an ice front.
A thick and extensive ice body attached to a coast and floating on the sea, gaining mass by flow from grounded glacier ice. See floating tongue, shelf ice. Ice shelves are much thicker than sea ice. C
urrently, nearly all are located in Antarctica. The mass balance of an ice shelf may have significant components of both gain and loss at the base.
A floating slab of ice of considerable thickness extending from the coast (usually of great horizontal extent with a very gently sloping surface), often filling embayments in the coastline of an ice s
heet. Nearly all ice shelves are in Antarctica, where most of the ice discharged into the ocean flows via ice shelves.
Floating ice sheet of considerable thickness attached to a coast, and nourished by the accumulation of snow and often by the seaward extension of land glaciers. Limited areas may be aground as ice ris
es. The seaward edge is termed an ice front.