Pobeda Ice Island

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 160 km off the East Antarctica Coast of Queen Mary Land, Australian Antarctic Territory, that exists periodically.

Periodic Formation

The ice island is created and vanishes periodically. It is created by calving of a tabular iceberg off Denman Glacier in the east part of Shackleton Ice Shelf, which drifts northwest and then runs aground a shoal north of the ice shelf. The iceberg remains locked in this position there for a decade or more, until it thins enough to free itself and drift into the open ocean where it breaks up and the fragments melt like ordinary icebergs. 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

The geographic term Island is misleading, since it is a tabular iceberg with nearly vertical sides and a flat top. The object is at least 27 meters high (above water level). According to Physics rules, this corresponds to one ninth or 11 percent of the total thicknes. Therefore the iceberg reaches at least 216 meters below sea level, and the least depth of the shoal must be less than that.

Pobeda is um to 70 km long and 36 km wide, and has an area of 1,500 km².

History

At this position, an ice island was first sighted by the United States Exploring Expedition, led by Charles Wilkes, in February 1840. It prevented his westward passage around the Antarctic coast, and he named it "Termination Land".

A grounded berg was in place during Mawson's 1911-13 AAE (when he renamed it "Termination Ice Tongue"), but not during his 1929-31 BANZARE expedition.

It was back again in 1960, when a Soviet Expedition renamed it again, as Pobeda Ice Island, and established a temporary station on it. This one disappeared sometime in the 1970s, to be replaced by a new berg that calved in 1985. That also disappeared in 2003 or 2004. There is no ice island there at present.

Pobeda Canyon

About 200 km north of Pobeda Ice Island lies "Pobeda Canyon", an oceanic trench so named in 1956 by A. P. Lizitsin [http://ngdc.noaa.gov/mgg/gebco/SCUFN15REP.pdf] . It is located between coord|62|30|S|100|15|E and coord|64|30|S|097|35|E.

External links

* [http://www.antarktis.ch/62.htm coordinates, height, station operations]
* [http://nsidc.org/data/iceshelves_images/shackleton.html satellite map of the area]
* [http://data.aad.gov.au/aadc/gaz/display_name.cfm?gaz_id=119994 Pobeda Station]
* [http://data.aad.gov.au/aadc/mapcat/search_mapcat_results.cfm overview of maps]

Literature

* Bernard Stonehouse: "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]