Pobeda Ice Island
Encyclopedia
Pobeda Ice Island, original Russian
name остров Победы (остров = Island, Победа = Victory, meaning Pobeda Island or Victory Island), is an ice island in the Mawson Sea
. It is located 160 km (99.4 mi) off the coast of Queen Mary Land, Australian Antarctic Territory
, East Antarctica
. This island, which exists periodically, is formed by the running aground of a tabular iceberg.
of an enormous block of ice from Denman Glacier
, located in the eastern part of Shackleton Ice Shelf
. The resulting tabular iceberg drifts northwest until it runs aground upon a shoal
north of the ice shelf. The iceberg remains locked in this position there for a decade or more, until has remodeled enough to free itself from the shoal. It then drifts into the open ocean
, where it breaks into fragments. These iceberg fragments eventually melt as they drift into warmer waters. The floating tongue of the Denman Glacier, fed by ice from the interior of Antarctica, advances until a new large berg is calved about every 40 to 50 years.
The term "island"
is technically incorrect, since this geographic feature is in reality a tabular iceberg with nearly vertical sides and a flat top.
Laws of physics dictate that 11% of an iceberg will extend above the water level (in salt water), while the remainder will be submerged. In the case of Pobeda Ice Island, whose flat surface is roughly 27 metres (89 ft) above sea level, this means that the iceberg extends to a depth of roughly 216 metres (709 ft) below sea level, and its total height is approximately 243 metres (797 ft). The further implication is that the ocean floor is also roughly 216 metres (709 ft) below sea level, at the point of the shoal.
, led by Charles Wilkes
, in February 1840. It prevented his westward passage around the Antarctic coast, and he named it Termination Land.
Douglas Mawson
renamed the island Termination Ice Tongue when he encountered it on the 1911-13 Australasian Antarctic Expedition
. No island was noted however at that location, when he returned during his 1929-31 BANZARE expedition.
A Soviet Expedition came across the island in 1960 and renamed it again, this time as Pobeda Ice Island, named for Soviet victory over the Axis powers in the Great Patriotic War. They even established a temporary research station on the island. Pobeda disappeared sometime in the 1970s, to be replaced by a new berg that calved in 1985. That one also disappeared in 2003 or 2004. There is currently no ice island at this location.
so named in 1956 by A. P. Lizitsin http://ngdc.noaa.gov/mgg/gebco/SCUFN15REP.pdf. It is located between 62°30′S 100°15′E and 64°30′S 097°35′E.
Russian language
Russian is a Slavic language used primarily in Russia, Belarus, Uzbekistan, Kazakhstan, Tajikistan and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Turkmenistan and Estonia and, to a lesser extent, the other countries that were once constituent republics...
name остров Победы (остров = Island, Победа = Victory, meaning Pobeda Island or Victory Island), is an ice island in the Mawson Sea
Mawson Sea
Mawson Sea is an area of the sea along the Queen Mary Land coast of East Antarctica between the Shackleton Ice Shelf in the west and Vincennes Bay in the east. West of it, on the western side of Shackleton Ice Shelf, is the Davis Sea. To the east is Bowman Island and Vincennes Bay.Two important...
. It is located 160 km (99.4 mi) off the coast of Queen Mary Land, Australian Antarctic Territory
Australian Antarctic Territory
The Australian Antarctic Territory is a part of Antarctica. It was claimed by the United Kingdom and placed under the authority of the Commonwealth of Australia in 1933. It is the largest territory of Antarctica claimed by any nation...
, East Antarctica
East Antarctica
East Antarctica, also called Greater Antarctica, constitutes the majority of the Antarctic continent, lying on the Indian Ocean side of the Transantarctic Mountains...
. This island, which exists periodically, is formed by the running aground of a tabular iceberg.
Periodic Formation
The ice island is created and vanishes periodically. It is created by the calvingIce calving
Ice calving, also known as glacier calving or iceberg calving, is a form of ice ablation or ice disruption. It is the sudden release and breaking away of a mass of ice from a glacier, iceberg, ice front, ice shelf, or crevasse...
of an enormous block of ice from Denman Glacier
Denman Glacier
Denman Glacier is a glacier wide, descending north some , which debouches into Shackleton Ice Shelf east of David Island, Queen Mary Land. It was discovered in November 1912 by the Western Base Party of the Australasian Antarctic Expedition under Sir Douglas Mawson. Mawson named the glacier for...
, located in the eastern part of Shackleton Ice Shelf
Shackleton Ice Shelf
Shackleton Ice Shelf is an extensive ice shelf fronting the coast of East Antarctica for about 384 km , projecting seaward about 145 km in the western portion and 64 km in the east. It occupies an area of 33,820 km². It is part of Mawson Sea and separates the Queen Mary Coast to the west from...
. The resulting tabular iceberg drifts northwest until it runs aground upon a shoal
Bank (topography)
A bank, sometimes referred to as a fishing bank, is an area on the continental shelf which is shallow compared to its surrounding area, such as a shoal or the top of an underwater hill. Somewhat like continental slopes, ocean banks slopes can upwell as tidal and other flows intercept them,...
north of the ice shelf. The iceberg remains locked in this position there for a decade or more, until has remodeled enough to free itself from the shoal. It then drifts into the open ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
, where it breaks into fragments. These iceberg fragments eventually melt as they drift into warmer waters. The floating tongue of the Denman Glacier, fed by ice from the interior of Antarctica, advances until a new large berg is calved about every 40 to 50 years.
Data
Pobeda Ice Island is variable in its dimensions, but is commonly up to 70 km (43.5 mi) long and 36 km (22.4 mi) wide, with an area of 1500 km² (579 sq mi).The term "island"
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
is technically incorrect, since this geographic feature is in reality a tabular iceberg with nearly vertical sides and a flat top.
Laws of physics dictate that 11% of an iceberg will extend above the water level (in salt water), while the remainder will be submerged. In the case of Pobeda Ice Island, whose flat surface is roughly 27 metres (89 ft) above sea level, this means that the iceberg extends to a depth of roughly 216 metres (709 ft) below sea level, and its total height is approximately 243 metres (797 ft). The further implication is that the ocean floor is also roughly 216 metres (709 ft) below sea level, at the point of the shoal.
History
At this position, an ice island was first sighted by the United States Exploring ExpeditionUnited States Exploring Expedition
The United States Exploring Expedition was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States from 1838 to 1842. The original appointed commanding officer was Commodore Thomas ap Catesby Jones. The voyage was authorized by Congress in...
, led by Charles Wilkes
Charles Wilkes
Charles Wilkes was an American naval officer and explorer. He led the United States Exploring Expedition, 1838-1842 and commanded the ship in the Trent Affair during the American Civil War...
, in February 1840. It prevented his westward passage around the Antarctic coast, and he named it Termination Land.
Douglas Mawson
Douglas Mawson
Sir Douglas Mawson, OBE, FRS, FAA was an Australian geologist, Antarctic explorer and Academic. Along with Roald Amundsen, Robert Falcon Scott, and Ernest Shackleton, Mawson was a key expedition leader during the Heroic Age of Antarctic Exploration.-Early work:He was appointed geologist to an...
renamed the island Termination Ice Tongue when he encountered it on the 1911-13 Australasian Antarctic Expedition
Australasian Antarctic Expedition
The Australasian Antarctic Expedition was an Australasian scientific team that explored part of Antarctica between 1911 and 1914. It was led by the Australian geologist Douglas Mawson, who was knighted for his achievements in leading the expedition. In 1910 he began to plan an expedition to chart...
. No island was noted however at that location, when he returned during his 1929-31 BANZARE expedition.
A Soviet Expedition came across the island in 1960 and renamed it again, this time as Pobeda Ice Island, named for Soviet victory over the Axis powers in the Great Patriotic War. They even established a temporary research station on the island. Pobeda disappeared sometime in the 1970s, to be replaced by a new berg that calved in 1985. That one also disappeared in 2003 or 2004. There is currently no ice island at this location.
Pobeda Canyon
About 200 km (124.3 mi) north of Pobeda Ice Island lies Pobeda Canyon, an oceanic trenchOceanic trench
The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor....
so named in 1956 by A. P. Lizitsin http://ngdc.noaa.gov/mgg/gebco/SCUFN15REP.pdf. It is located between 62°30′S 100°15′E and 64°30′S 097°35′E.
See also
- List of Antarctic islands south of 60° S
- Thwaites Iceberg Tongue
External links
Literature
- Bernard StonehouseBernard StonehouseBernard Stonehouse is a British scientist who specialised in polar research and popular science. He was born in Hull on 1 May 1926. He joined the Royal Navy in 1944, and served from 1946–1950 for the Falkland Islands Dependencies Survey...
: Encyclopedia of Antarctica and the Southern Oceans. Wiley, Chichester/Hoboken 2002, ISBN 0-471-98665-8, S. 200 http://books.google.de/books?id=6uFd1mICC98C&pg=PA378&dq=Encyclopedia+of+Antarctica&sig=_K6JEn_RMgFikX8jVm5D_k-mZfY#PPA200,M1