Wednesday, October 28, 2009

Antarctica

Antarctica, with an area of 14,000,000 sq km, surrounds and covers the South Pole. The continent is the coldest and iciest region on earth. The Antarctic icecap, which has been formed from layers of snow pressed together over millions of years, buries 98 per cent of the continent and forms the largest body of fresh water or ice in the world. The average thickness of ice on this continent is approximately two to five kilometres. Underneath the ice, Antarctica has moun­tains, lowlands and valleys.

The Transantarctic Mountains, made up of several ranges, cross the entire continent and divide it into two natural land regions-East Antarctica and West Antarctica. East Antarctica faces the Atlantic and Indian Oceans and covers more than half the continent. The region consists of rocks that are more than 570 million years old. The central part of East Antarctica is a plateau about 3000 metres above the sea level. The South Pole, the southern-most point on the earth, lies on this plateau. The south magnetic pole, the southern part indicated by compass needles, is also located in East Antarctica.

West Antarctica faces the Pacific Ocean. Much of the region lies below sea level and does not contain the old rock of East Antarctica. West Antarctica developed later as part of the Ring of Fire, a string of volcanoes encircling the Pacific Ocean. West Antarctica includes several moun­tain ranges and volcanoes. The Antarctic Peninsula is a mountainous strip of land pointing towards South America. The peninsula is said to be a continuation of the Andes mountain chain of South America. Near the peninsula are several islands; the South Shetland Islands include the Deception Island, an active volcano. Vinson Massif, the highest point in Antarctic (5,140 m), is part of the Ellsworth Mountains near the peninsula. Mount Erebus, Antarctica's most active volcano, lies on the Ross Island.

The Ross Sea and the Weddell Sea are gulfs that cut into Antarctica from opposite ends of the Transantarctic Mountains. There are smaller bays indenting the coastline.
Temperatures in Antarctica rarely reach above O°c. At the South Pole, temperatures as low as -95°C have been recorded during winters. The Antarctic winter lasts from May until August. Summer lasts from December until February. Extremely cold dry conditions exist on the inland plateau. The plateau has one of the driest climates on earth; it receives no rain and little new snow each year. Relatively mild and moist conditions mark the coastal regions.
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