The Origins of Antarctica
Antarctica is the most remote of the seven continents. Situated around the South Pole of the Earth's axis, the continent covers an area of approximately 5.4 million square miles, making it the fifth largest continent. The nearest landmass, South America, is more than 600 miles north. This isolation ensured that no explorer would even sight the continent until 1820.
Discovering the origins of Antarctica requires traveling back about 500 million years. Geologically, Antarctica can be split into two sections: East (Greater) and West (Lesser) Antarctica.
East Antarctica was originally part of the supercontinent known as Gondwanaland, which also consisted of South America, Africa, Madagascar, southern India and Australia. Gondwanaland is known to have existed from around 500 million years ago to about 160 million years ago. About 280 million years ago the part of Gondwanaland that is East Antarctica was situated over the South Pole, but then the supercontinent started to move north and, as it did so, the climate grew warmer. At about 160 million years ago, Gondwanaland began to break up, and the various pieces of the supercontinent started to drift apart from one another. By about 25 million years ago, East Antarctica moved into its current position over the South Pole, which is where it became covered in ice.
West Antarctica is much younger than East Antarctica, and, although some rocks of up to 570 million years old have been found on the Antarctic Peninsula, the majority of rocks are between 2 and 225 million years old. Whereas East Antarctica consists of part of a shield of ancient continental rock, West Antarctica consists of a number of separate blocks of younger continental rock that joined to the East Antarctic shield late in its evolution. The rocks of West Antarctica show several similarities to the rocks of South America, and the northern mountains of the Antarctic Peninsula and the South Sandwich Islands are an extension of the volcanic arc of the Andean chain. It is in the Sentinel Range of West Antarctica that the highest mountains in Antarctica are situated. The highest mountains are Vinson Massif (16,067 feet), followed by Mount Tyree (15,896 feet), Mount Shinn (15,752 feet) and Mount Gardner (15,374 feet), respectively.
Early expeditions during the so-called "Heroic Age of Antarctic Exploration" (1895-1922) recognized the phenomenal value of Antarctica as a scientific resource. Norwegian explorer Carsten Borchgrevink's discovery of lichens on the Antarctic Peninsula in 1895 and British explorer Robert Falcon Scott's collection of geological samples during his last fateful expedition in 1912 are two of the earliest examples.
Since then scientific research in Antarctica has developed to a comprehensive level in a wide variety of disciplines and programs: geology and rock drilling, geophysics and seismic profiling, glaciology and snow sampling, marine biology and seal studies, oceanography and bottom sampling, and space science and ionospheric measurement. National Antarctic research programs such as the United States Antarctic Program, the British Antarctic Survey and the South African National Antarctic Expedition have built up complex logistical organizations with ice-breaking ships, ski-equipped aircraft and permanent scientific bases. Currently, approximately 50 permanent and temporary scientific bases are on the Antarctic continent, and up to 3,000 scientists may visit during the Antarctic summer.
Science would not be possible in the Antarctic if it were not for the international agreement known as the Antarctic Treaty. The Antarctic Treaty arose as a way of settling the disputes that ensued from the competing territorial claims of the early national Antarctic expeditions.
The origins of the Treaty stretch back to 1939, when President Roosevelt's initiative for U.S. sovereignty over Antarctica caused Chile to stake its territorial claim on the continent in the following year. The resulting political confrontation between Chile, Argentina and the United Kingdom led the United States to suggest a trustee arrangement for Antarctica overseen by the United Nations. Opposition to this led to the suggestion that the authority and control of the area should be vested in the hands of interested countries, which would allow for the promotion of scientific research in the region through an international agreement.
After extensive negotiation and the success of the International Geophysical Year in 1957-58, representatives from Argentina, Australia, Chile, France, Japan, New Zealand, Norway, South Africa, the United Kingdom, the United States and the USSR convened in Washington D.C. to sign the Antarctic Treaty, which was subsequently ratified in 1961.
The main provisions of the Treaty are:
Over the last 40 years, additional safekeeping measures have evolved from the original Antarctic Treaty. The Protocol on Environmental Protection to the Antarctic Treaty was signed in 1991 and provides for the environmental management of all activities in Antarctica. It governs environmental impact assessment, protection of flora and fauna, waste management and disposal, avoidance of marine pollution and designation of protected areas. It is legally enforced in the countries that have ratified it. The overwhelming achievement of the Antarctic Treaty has been the shared responsibility for this unique environment. Indeed, the Antarctic Treaty may well be considered the most advanced international agreement of all time.
The Subantarctic Islands
The Antarctic Convergence is the boundary around the Antarctic in which Antarctic Bottom Water, the cold dense water of the Southern Oceanformed when ice shelves melt and the water sinks to the ocean flooris drawn north away from the Antarctic continent where it meets warmer water and sinks underneath it. Where the two types of water mix, upwelling of nutrients from the Antarctic Bottom Waterin which oxygen dissolves easily, encouraging the breeding of marine organismsprovides an immense supply of food for seals, whales, penguins and seabirds. The boundary of the Convergence has changed throughout time and is the subject of continuing oceanographic investigation. The Antarctic Convergence profoundly influences the climates and ecosystems of the islands surrounding Antarctica.
The most southern islands, the Antarctic coastal islands such as Berkner Island and Ross Island, are mainly ice-covered and influenced by the cold, dry air flowing down off the Antarctic continent. Moving further north, the maritime islands, such as Elephant Island and Bouvetøya, are influenced by the maritime climate of the Southern Ocean and can be surrounded by pack ice in winter, as Sir Ernest Shackleton found out in his attempts to rescue the men on Elephant Island. Many of these islands have huge numbers of breeding penguins.
South Georgia is one of the group of subantarctic islands, along with Heard and MacDonald islands, which are on the other side of the continent. These lie near the Antarctic Convergence and, although they are glaciated, they are not usually surrounded by pack ice in winter. They are renowned for the incredibly powerful katabatic winds that emerge from their interiors and roar down to the coast. (Katabatic winds are caused by dense, cold air rushing downhill.) Their close proximity to the Convergence means that they are oases for animal life and breeding grounds for king penguins, wandering albatrosses, elephant seals and fur seals, amongst many other animals.
The last group of islands are those lying between the Antarctic and Subtropical Convergences, including the Falkland Islands and the Îles des Kerguelen. These temperate islands all have ice-free coastlines and a rich, lush vegetation with tussock grass and treeless peaty uplands due to their wet, rainy climate.
It is the elephant and fur seal populations of the subantarctic islands that first attracted human explorers to the area. At the end of the 18th century, British and New England ships sailed south to start exploiting the abundance of seals on South Georgia. After the fur seal populations had been severely depleted, elephant seals were slaughtered for the oil processed from the thick layer of blubber insulating them in the frigid water. But it was not just the seals that were a resource for humans. The sealing expeditions could not fail to notice that the waters of South Georgia teemed with whales.
In 1904 Carl Anton Larsen established Grytviken whaling station in Cumberland Bay on South Georgia. This was the beginning of a very successful industry on South Georgia, and six more whaling stations were established on the island: Godthul, Ocean Harbour, Prince Olav Harbour, Leith Harbour, Husvik and Stromness. Between 1904 and the closure of the last whaling station in 1965, a total of 175,250 whales were taken off South Georgia, including 41,515 blue whales. One of these, a female, measured at 110 feet long, was the largest animal ever recorded.
The whaling stations were popular launching points for the many expeditions of the so-called "Heroic Age of Antarctic Exploration," and both Grytviken and Stromness were crucial to Shackleton's Endurance expedition.
To see 360° panoramas from Antarctica and the Subantarctic, visit the NOVA/PBS Online Adventure site by clicking the logo below.
For more information about Antarctica, Visit NOVA's Warnings in the Ice site: www.pbs.org/wgbh/nova/warnings/
Photo Credits: © 2000 Stephen Venables
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