|
Geography
Antarctica is a desert. Her snow is ancient, there is less yearly precipitation
here than in Sahara. She is the worlds fifth largest continent
(larger than Australia) and the highest situated, driest,
coldest and most silent (when there is no wind) continent in the
world.
She is divided into
Greater (east) and Lesser (west) Antarctica. Greater Antarctica
is one stable plate, whereas the lesser Antarctica consists of
several smaller, moving plates. The South Pole is on Greater
Antarctica.
Greater and lesser
Antarctica are divided by the Transantarctica mountain range and
there is also a circle of mountains surrounding the coast.
The area in between the
mountains appears to be flat snow. Instead, there are mountain
ranges the size of Alps (!) covered by ice, at places pushed by
the thick ice up to 2000ft (600m) below sea level. The ice sheet, at
places thicker than 2.5 miles (4km), averages 1.7 miles (2,7km) in thickness with an
area of 5.2 sq miles (13,5 million sq km).
The ice is the result of
snowfall over millions of years. All this snow, frozen and
preserved, tells the history of past climates. Drilling a sample
shows the chemicals and gases trapped in the ice thousands of
years ago. This is helpful in understanding cyclic global
warming.
Elevation South Pole:
2835 m (9300 ft), equivalent of 10660ft (3230m) due to the cold and polar
location. Only 50% of sea level oxygen is available to humans,
as the earth atmosphere is most shallow at the North and South
Poles. Altitude sickness is therefore common to in-flying
visitors.
Elevation Antarctica:
Average altitude of Arctic Plateau 7500ft (2165m), highest
plateau 13036ft (3950m).
Highest Mountain:
Mt Vinson, 16 067ft (4897m) (climbed first by US in 1966).
Highest (active) volcano:
Mt Erebus 12 444ft (3795m). (1979 a NZ tourist plane crashed
here, killing all 257 aboard).
Lowest point:
-2550 m WA (close to the Hollick-Kenyon Plateau).
Area:
5,49 million sq miles (14,2 million sq km). 1:10th of earth's surface, 1,5
times United States.
The continent is varied with mountains, volcanoes, deserts,
islands and coastal areas.
Geographic South Pole:
90 degrees South (EA). The lower axis of the earth's rotation.
Ice thickness 1,7 miles (2,8km).
Geomagnetic South Pole:
East Antarctica, close to Vostok. The lower axis of the earth's
magnetic field.
Magnetic South Pole:
App 65 degrees south, 140 degrees east. The point at which the
compass will point in the Southern Hemisphere. The MSP move a
few kilometers yearly as the Earth's magnetic field changes.
Ice area:
98% of the land is covered by ice, around 40 million years old.
This is 90% of the earth's ice, including 70% of the worlds
freshwater. Volume 7.2 million cubic miles (30 million cubic km), area (13 586 000 sq km).
If it were to melt, the
earth's waters would rise 220 ft (70m).
Thickest ice:
15 670 ft (4776m) (measured with Echo-sounding from aircraft).
Ross Ice Shelf:
Antarctica's largest ice shelf (larger than France). 3300ft (1000m)
thick, 200 000 sq miles (520 000 sq km) large. The shelf reaches to the edge of
land, there tipping over into the sea. The object of many
Antarctic cruise photographs.
Dry deserts:
East Antarctica. Free of snow or ice, also called
"Oases", they cover 3000 sq miles (7750 sq km). Main deserts are
the Victoria, Wright and Taylor dry valleys. No precipitation
for 2 million years. Exposed rock surface. Free of ice 4 million
years. At least 3 billion years old. The oldest rock on earth
was found here, dating back about 3.93 billion years. The rocks
are polished by the wind into strange formations. Freeze-dried,
mummified skeletons of seals and penguins are found here. The
dry valleys of Antarctica are considered by scientists the earth's nearest
equivalent to the terrain of Mars.
Frozen lakes:
Saltwater basins, partially or totally frozen. Some are so
saline that they won't freeze even at -76F (-60C). The water is like
syrup. On others there are ice crusts that, like lenses, keep
the water warm. The lakes were formed by glaciers about 1200
years ago; the lids are sometimes 15ft (4,5m) thick. The water smells
like rotten eggs but is full of ancient microorganisms. Some
lakes are half-fresh, half-salt water and heated by the earth's
core heat. Largest frozen lake: Vostok, EA.
|