Transantarctic Mountains

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Transantarctic Mountains
Range
The Transantarctic Mountains in northern Victoria Land near Cape Roberts
Continent	Antarctica

Highest point	Mount Kirkpatrick
- elevation	4,528 m (14,856 ft)
- coordinates	84°20′S 166°25′E / -84.333, 166.417

Period	Cenozoic

Aerial view of the Beardmore Glacier in 1956

Mount Herschel (3,335 m) in the Admiralty Mountains subrange, as seen from Cape Hallett

Blue ice covering Lake Fryxell in the Dry Valleys of the Transantarctic Mountains. The lake is formed from glacial meltwater 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 Transantarctic Mountains (abbreviated TAM) compose a mountain range in Antarctica which extend, with some interruptions, across the continent from Cape Adare in northern Victoria Land to Coats Land. These mountains serve as the division between East Antarctica and West Antarctica. They include a number of separately named mountain groups, which are often again subdivided into smaller ranges.

1 Geography
2 Biology
3 History
4 Geology
5 See also
6 External links

[edit] Geography

The mountain range stretches between the Ross Sea and the Weddell Sea the entire length of Antarctica, thence the name. With a total length of about 3,500 km, the Transantarctic Mountains are one of the longer mountain ranges on Earth. The 100–300 km wide range forms the boundary between East Antarctica and West Antarctica. The East Antarctic Ice Sheet bounds the TAM along their entire length on the Eastern Hemisphere side, while the Western Hemisphere side of the range is bounded by the Ross Sea in Victoria Land from Cape Adare to McMurdo Sound, the Ross Ice Shelf from McMurdo Sound to near the Scott Glacier, and the West Antarctic Ice Sheet beyond.

The summits and dry valleys of the TAM are some of the few places in Antarctica not covered by ice, the highest of which rise more than 4,500 metres (14,764 ft) above sea level. The Dry Valleys lie near McMurdo Sound and represent a special Antarctic phenomenon: landscapes that are snow and ice free due to the extremely limited precipitation and ablation of ice in the valleys. The highest mountain is 4,528 m high Mount Kirkpatrick in the Queen Alexandra Range. Isolated peaks surrounded by ice are referred to as nunataks.

[edit] Biology

Main article: Antarctic ecozone

Penguins, seals, and sea birds live along the Ross Sea coastline in Victoria Land, while life in the interior of the Transantarctics is limited to lichens, algae, and fungi.

[edit] History

The Transantarctic Mountains were first seen by Captain James Ross in 1841 from the Ross Sea. The range is a natural barrier that must be crossed to reach the South Pole from the Ross Ice Shelf. In 1908, while not making the pole, Ernest Shackleton's party was the first to cross the mountains, using the Beardmore Glacier. Robert Scott returned to the Beardmore in 1911, while Roald Amundsen crossed the range via the Axel Heiberg Glacier.

Much of the range remained unexplored until the late 1940's and 1950's, when missions such as Operation Highjump and the International Geophysical Year made extensive use of aerial photography and concentrated on a thorough investigation of the entire continent. The name "Transantarctic Mountains" were recommended in 1962 by the US-ACAN committee, a US authority for geographic names. This purely descriptive label (in contrast to many other geographic names of the seventh continent) is internationally accepted at present.

The Leverett Glacier in the Queen Maud Mountains is the planned route through the TAM for the overland supply road between McMurdo Station and Amundsen-Scott South Pole Station.

[edit] Geology

Main article: Geology of Antarctica

The Transantarctic Mountains are considerably older than other mountain ranges of the continent that are mainly volcanic in origin. The range was uplifted during the opening of the West Antarctic Rift to the east, beginning about 65 million years ago in the early Cenozoic.

The mountains consist of sedimentary layers lying upon a basement of granites and gneisses. The sedimentary layers include the Beacon Supergroup sandstones, siltstones, and coal deposited beginning in the Silurian period and continuing into the Jurassic. In many places the Beacon has been intruded by dikes and sills of Jurassic-age Ferrar Dolerite. Many of the fossils found in Antarctica are from locations within these sedimentary formations.

Ice from the East Antarctic ice sheet flows through the Transantarctic Mountains via a series of outlet glaciers into the Ross Sea, Ross Ice Shelf, and West Antarctic Ice Sheet. These glaciers generally flow perpendicular to the orientation of the range and define subranges and peak groups. It is thought that many of these outlet glaciers follow the traces of large-scale geologic faults.