Geography of Antarctica

From Wikipedia, the free encyclopedia

Photo of Booth Island in Antarctica

[1] higher resolution copy

The Blue ice covering Lake Fryxell, in the Transantarctic, comes from glacial meltpee from the Canada Glacier and other smaller glaciers. The fresh water stays on top of the lake and freezes, sealing in briny water below.

The continent of Antarctica is located mostly south of the Antarctic Circle. Physically Antarctica is divided in two by mountains close to the neck between the Ross Sea and the Weddell Sea. Western Antarctica and Eastern Antarctica correspond roughly to the eastern and western hemispheres relative to the Greenwich meridian. This usage has been regarded as Eurocentric by some, and the alternative terms Lesser Antarctica and Greater Antarctica (respectively) are sometimes preferred.

Western Antarctica is covered by the West Antarctic Ice Sheet. There has been some concern about this ice sheet, because there is a small chance that it will collapse. If it does, ocean levels would rise by a few metres in a very short period of time.

In some areas, the ice sheet rests on bedrock below sea level [2].

1 Statistics
2 Volcanoes
3 See also
4 External links

[edit] Statistics

Area

Total: 14 million km²
Land: 14 million km² (280,000 km² ice-free, 13.72 million km² ice-covered) (est.)
Note: Fifth-largest continent, following Asia, Africa, North America, and South America, but larger than Australia and the subcontinent of Europe

Land boundaries

None

Coastline

17,968 km

Maritime claims

None

Climate

Severe low temperatures vary with latitude, elevation, and distance from the ocean; East Antarctica is colder than West Antarctica because of its higher elevation; Antarctic Peninsula has the most moderate climate; higher temperatures occur in January along the coast and average slightly below freezing

Terrain

About 98% thick continental ice sheet and 2% barren rock, with average elevations between 2,000 and 4,000 meters; mountain ranges up to 4,892 meters; ice-free coastal areas include parts of southern Victoria Land, Wilkes Land, the Antarctic Peninsula area, and parts of Ross Island on McMurdo Sound; glaciers form ice shelves along about half of the coastline, and floating ice shelves constitute 11% of the area of the continent. The dry valleys of Antarctica are a particularly interesting region of Antarctica. Due to extreme winds and lack of precipitation, this area is devoid of any snow and barren earth is visible.

Elevation extremes

Lowest point: Southern Ocean 0 m, although in some areas the bedrock under the ice sheet is below sea level.
Highest point: Vinson Massif 4,892 m (Ellsworth Mountains)

Natural resources

None presently exploited; iron ore, chromium, copper, gold, nickel, platinum and other minerals, and coal and hydrocarbons have been found in small, uncommercial quantities

Land use

Other: 100% (ice 98%, barren rock 2%)

Irrigated land: 0 km² (1993)
Natural hazards: Katabatic (gravity-driven) winds blow coastward from the high interior; frequent blizzards form near the foot of the plateau; cyclonic storms form over the ocean and move clockwise along the coast; volcanism on Deception Island and isolated areas of West Antarctica; other seismic activity rare and weak
Environment - current issues: Ozone hole, sea level rise
Geography - note: The coldest, windiest, highest (2,300 m on average), and driest continent; during summer, more solar radiation reaches the surface at the South Pole than is received at the Equator in an equivalent period; mostly uninhabitable.

[edit] Volcanoes

There are four volcanoes on the mainland of Antarctica that are considered to be active on the basis of observed fumarolic activity or "recent" tephra deposits: Mount Melbourne (2,730 m) (74°21'S., 164°42'E.), a stratovolcano; Mount Berlin (3,500 m) (76°03'S., 135°52'W.), a stratovolcano; Mount Kauffman (2,365 m) (75°37'S., 132°25'W.), a stratovolcano; and Mount Hampton (3,325 m) (76°29'S., 125°48'W.), a volcanic caldera.

Several volcanoes on offshore islands have records of historic activity. Mount Erebus (3,795 m), a stratovolcano on Ross Island with 10 known eruptions and 1 suspected eruption. On the opposite side of the continent, Deception Island (62°57'S., 60°38'W.), a volcanic caldera with 10 known and 4 suspected eruptions, have been the most active. Buckle Island in the Balleny Islands (66°50'S., 163°12'E.), Penguin Island (62°06'S., 57°54'W.), Paulet Island (63°35'S., 55°47'W.), and Lindenberg Island (64°55'S., 59°40'W.) are also considered to be active.