The Drygalski Ice Tongue, Drygalski Barrier, or Drygalski Glacier Tongue is a

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

, on the

Scott Coast Scott Coast () is the portion of the coast of Victoria Land, Antarctica between Cape Washington and Minna Bluff. It was named by the New Zealand Antarctic Place-Names Committee in 1961 after Captain Robert Falcon Scott, Royal Navy, leader of the ...

, in the northern

McMurdo Sound McMurdo Sound is a sound in Antarctica. It is the southernmost navigable body of water in the world, and is about from the South Pole. Captain James Clark Ross discovered the sound in February 1841, and named it after Lt. Archibald McMurdo o ...

Ross Dependency The Ross Dependency is a region of Antarctica defined by a sector originating at the South Pole, passing along longitudes 160° east to 150° west, and terminating at latitude 60° south. It is claimed by New Zealand, a claim accepted only b ...

, north of

Ross Island Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound. Ross Island lies within the boundaries of Ross Dependency, an area of Antarctica claimed by New ...

. The Drygalski Ice Tongue is stable by the standards of Antarctica's icefloes, and stretches out to sea from the

David Glacier David Glacier is the most imposing outlet glacier in Victoria Land, Antarctica. It is named after the geologist Edgeworth David and is fed by two main flows which drain an area larger than 200,000 square kilometres of the East Antarctic platea ...

, reaching the sea from a valley in the

Prince Albert Mountains The Prince Albert Mountains () are a major mountain group in Antarctica over 320 km (200 mi) long. Located in Victoria Land, they run north–south between the Priestley and Ferrar glaciers. They were named for Prince Albert, the cons ...

Victoria Land Victoria Land is a region in eastern Antarctica which fronts the western side of the Ross Sea and the Ross Ice Shelf, extending southward from about 70°30'S to 78°00'S, and westward from the Ross Sea to the edge of the Antarctic Plateau. It ...

. The Drygalski Ice Tongue ranges from wide. Captain

Robert Falcon Scott Captain Robert Falcon Scott, , (6 June 1868 – c. 29 March 1912) was a British Royal Navy officer and explorer who led two expeditions to the Antarctic regions: the ''Discovery'' expedition of 1901–1904 and the ill-fated ''Terra Nov ...

, leader of the

British National Antarctic Expedition The ''Discovery'' Expedition of 1901–1904, known officially as the British National Antarctic Expedition, was the first official British exploration of the Antarctic regions since the voyage of James Clark Ross sixty years earlier (1839–18 ...

(1901-1904), discovered the Drygalski Ice Tongue in January 1902 and named it for Professor

Erich von Drygalski Erich Dagobert von Drygalski (; February 9, 1865 – January 10, 1949) was a German geographer, geophysicist and polar scientist, born in Königsberg, East Prussia. Between 1882 and 1887, Drygalski studied mathematics and natural science at t ...

, a contemporary German explorer then in Antarctica. The glacier that feeds the ice tongue was named after

Edgeworth David Sir Tannatt William Edgeworth David (28 January 1858 – 28 August 1934) was a Welsh Australian geologist and Antarctic explorer. A household name in his lifetime, David's most significant achievements were discovering the major Hunter V ...

. David and

Douglas Mawson Sir Douglas Mawson OBE FRS FAA (5 May 1882 – 14 October 1958) was an Australian geologist, Antarctic explorer, and academic. Along with Roald Amundsen, Robert Falcon Scott, and Sir Ernest Shackleton, he was a key expedition leader during ...

crossed the ice tongue in 1908/09 as part of the ''Nimrod'' Expedition. The ''Terra Nova'' Northern Party expedition did the same in 1912 during their return journey to

Cape Evans Cape Evans is a rocky cape on the west side of Ross Island, Antarctica, forming the north side of the entrance to Erebus Bay. History The cape was discovered by the British National Antarctic Expedition, 1901–04, under Robert Falcon Scott, wh ...

. The name Drygalski Ice Tongue is unusual, as it is now common to give the same name to a glacier and its glacier tongue and refer to the seaward extension as a glacier tongue. The Drygalski Ice Tongue is thought to be at least 4,000 years old. The recent history of the combined glacier and ice tongue used analysis of rocks deposited along the margin of the David Glacier to identify a rapid thinning event initiated over 7,000 years ago that endured for ~ 2,000 years. The David Glacier grounding line, where the ice leaves the shore and begins to float, is in a depth of ~. The floating ice tongue itself is a significant factor contributing to the frequent formation of the

Terra Nova Bay Terra Nova Bay is a bay which is often ice free, about long, lying between Cape Washington and the Drygalski Ice Tongue along the coast of Victoria Land, Antarctica. It was discovered by the British National Antarctic Expedition (known as the ...

polynya. The

polynya A polynya () is an area of open water surrounded by sea ice. It is now used as a geographical term for an area of unfrozen seawater within otherwise contiguous pack ice or fast ice. It is a loanword from the Russian полынья (), which re ...

enables both production of sea ice and high salinity seawater. The floating ice is in places only 300 m thick, with between of ocean beneath. The floating glacier also forms the southern bound of the Nansen Ice Shelf. This small ice shelf is subject to strong

katabatic winds A katabatic wind (named from the Greek word κατάβασις ''katabasis'', meaning "descending") is a drainage wind, a wind that carries high-density air from a higher elevation down a slope under the force of gravity. Such winds are sometim ...

. It is also possibly to observe free-flowing

meltwater Meltwater is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves over oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reducing. Meltwater can be ...

on its surface in summer conditions. In 2016 a long section of the ice shelf calved to form two large icebergs. On March–April 2005, a iceberg designated B-15A hit the ice tongue breaking off two pieces, each with a surface area of about . This iceberg is a remnant of Iceberg B-15, which calved from the

Ross Ice Shelf The Ross Ice Shelf is the largest ice shelf of Antarctica (, an area of roughly and about across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than long, and between hi ...

in 2000. Scientists are also concerned for several

penguin Penguins (order (biology), order List of Sphenisciformes by population, Sphenisciformes , family (biology), family Spheniscidae ) are a group of Water bird, aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: on ...

colonies which have been isolated from the open sea by the two large bodies of ice. At the end of March 2006, another iceberg coming from the Ross Ice Shelf, named C-16, hit the ice tongue, breaking off another large piece (more than ). Both of these incidents are described in a studyMacAyeal, D.R., Okal, M.H., Thom, J.E., Brunt, K.M., Kim, Y.J. and Bliss, A.K., 2008. Tabular iceberg collisions within the coastal regime. Journal of Glaciology, 54(185), pp.371-386. that benefited from the fortuitous presence of a

GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...

beacon on one of the icebergs.

References

External links

Envisat: Antarctica B-15A iceberg monitoring in Ross Sea
Bodies of ice of the Ross Dependency Prince Albert Mountains Glaciers of Scott Coast {{ScottCoast-glacier-stub

See also

References

External links