Geography | |
---|---|
Location | Antarctica |
Coordinates | 79°30′S47°30′W / 79.500°S 47.500°W |
Area | 44,000 km2 (17,000 sq mi) |
Area rank | 31st |
Length | 320 km (199 mi) |
Width | 150 km (93 mi) |
Highest elevation | 869 m (2851 ft) |
Highest point | Thyssenhöhe |
Administration | |
Administered under the Antarctic Treaty System | |
Demographics | |
Population | 0 (2000) |
Berkner Island (also known as the Berkner Ice Rise or as Hubley Island) is an Antarctic ice rise, where bedrock below sea level has caused the surrounding ice sheet to create a dome. If the ice cap were removed, the island would be underwater. [1] Berkner Island is completely ice-covered and is about 320 kilometres (200 mi) long and 150 kilometres (93 mi) wide, with an area of 44,000 km2 (17,000 sq mi). It is surrounded by the Filchner-Ronne Ice Shelf. The northernmost point of the Berkner is about 20 kilometres (12 mi) from the open sea. It lies in the overlapping portion of the Argentine and the British Antarctic territorial claims.
The island rises to 869 m (2,850 ft) (975 m or 3,200 ft, according to other sources) and separates the Ronne Ice Shelf from the Filchner Ice Shelf. It is characterized by two domes, Reinwarthhöhe in the north (698 m or 2,290 ft), and Thyssenhöhe in the south (869 m or 2,851 ft). It is indented by three bays on the eastern side, which are, from north to south, the McCarthy Inlet, the Roberts Inlet, and the Spilhaus Inlet. The southern tip is named the Mulvaney Promontory. Gould Bay is on the north coast. Berkner Island is about 150 km (93 mi) west of Luitpold Coast, Coats Land, the closest mainland of Eastern Antarctica. The Hemmen Ice Rise is 17 km (10.6 mi) off the northwest corner of Berkner Island.
Berkner Island was discovered by members of the United States-International Geophysical Year party from Ellsworth Station during the 1957–1958 season. It was named by the United States Advisory Committee on Antarctic Names after American physicist Lloyd Berkner, engineer with the Byrd Antarctic Expedition (1928–1930). [2]
Since 1990, Berkner Island has been a jumping-off point for a number of long-distance polar expeditions. Ben Saunders has planned an unsupported journey from the island to the South Pole and back, [3] and it was the start point of Henry Worsley's attempt to cross the Antarctic in 2015–16. [4]
In the 1994–1995 field season, the British Antarctic Survey (BAS), Alfred Wegener Institute and the Forschungsstelle für Physikalische Glaziologie of the University of Münster cooperated in a project drilling ice cores on the North (Reinwarthhöhe) and South (Thyssenhöhe) Domes of the island. [5] Between 2002 and 2005 a 948 meters (3,110 feet) core was drilled through to the bed at Thyssenhöhe by a team from BAS and the Laboratoire de Glaciologie et Géophysique de l’Environnement, Grenoble, [6] and radar work in 2005 and 2010-11 confirmed the existence of the Raymond Effect. [7] [8]
A 500 ha site on fast ice 5 kilometers (3.1 miles) north of the area where the Ronne Ice Shelf joins the north-western coast of Berkner Island, about 90 kilometers (56 miles) to the northwest of Gould Bay, has been identified as an Important Bird Area by BirdLife International because it supports an emperor penguin colony. The size of the colony was estimated as about 8,000 individual birds, based on 2009 satellite imagery. [9]
The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha Coast, Queen Maud Land. To the east of Cape Norvegia is the King Haakon VII Sea. Much of the southern part of the sea is covered by a permanent, massive ice shelf field, the Filchner-Ronne Ice Shelf.
An ice shelf is a large platform of glacial ice floating on the ocean, fed by one or multiple tributary glaciers. Ice shelves form along coastlines where the ice thickness is insufficient to displace the more dense surrounding ocean water. The boundary between the ice shelf (floating) and grounded ice is referred to as the grounding line; the boundary between the ice shelf and the open ocean is the ice front or calving front.
The Filchner–Ronne Ice Shelf or Ronne–Filchner Ice Shelf is an Antarctic ice shelf bordering the Weddell Sea.
Roosevelt Island is the second largest ice rise of Antarctica and world-wide, after Berkner Island. Despite its name, it is not an island, since the bedrock below the ice at its highest part is below sea level. It is about 130 km (81 mi) long in a NW-SE direction, 65 km (40 mi) wide and about 7,500 km2 (2,896 sq mi) in area, lying under the eastern part of the Ross Ice Shelf of Antarctica. Its central ridge rises to about 550 m (1,804 ft) above sea level, but this and all other elevations of the ice rise are completely covered by ice, so that it is invisible at ground level.
West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of that continent that lies within the Western Hemisphere, and includes the Antarctic Peninsula. It is separated from East Antarctica by the Transantarctic Mountains and is covered by the West Antarctic Ice Sheet. It lies between the Ross Sea, and the Weddell Sea. It may be considered a giant peninsula, stretching from the South Pole towards the tip of South America.
The Amery Ice Shelf is a broad ice shelf in Antarctica at the head of Prydz Bay between the Lars Christensen Coast and Ingrid Christensen Coast. It is part of Mac. Robertson Land. The name "Cape Amery" was applied to a coastal angle mapped on 11 February 1931 by the British Australian New Zealand Antarctic Research Expedition (BANZARE) under Douglas Mawson. He named it for William Bankes Amery, a civil servant who represented the United Kingdom government in Australia (1925–28). The Advisory Committee on Antarctic Names interpreted this feature to be a portion of an ice shelf and, in 1947, applied the name Amery to the whole shelf.
Henry Ice Rise is a triangular-shaped ice rise about 70 miles (110 km) long located between Korff Ice Rise and the southern portion of Berkner Island in the Ronne Ice Shelf, Antarctica. It was first visited by the United States International Geophysical Year geophysical traverse party from Ellsworth Station, 1957–58, and was named by the Advisory Committee on Antarctic Names after Captain Clifford D. Henry of the Military Sealift Command, a veteran American polar sea captain and master of USNS Private John R. Towle (T-AK-240). Henry died aboard his ship, February 16, 1975, while returning from his fourteenth voyage to Antarctica in support of the U.S. Antarctic Research Program.
Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica, responsible for about 25% of Antarctica's ice loss. The glacier ice streams flow west-northwest along the south side of the Hudson Mountains into Pine Island Bay, Amundsen Sea, Antarctica. It was mapped by the United States Geological Survey (USGS) from surveys and United States Navy (USN) air photos, 1960–66, and named by the Advisory Committee on Antarctic Names (US-ACAN) in association with Pine Island Bay.
An ice rise is a clearly defined elevation of the otherwise very much flatter ice shelf, typically dome-shaped and rising several hundreds of metres above the surrounding ice shelf . An ice rise forms where the ice shelf touches the seabed due to a locally increased elevation of the seabed, which however remains below sea level.. The ice shelf flows over the seabed elevation, completely covering it with ice, thereby forming an ice rise. The resulting stress increases cause crevasse formation around the ice rise.
Hemmen Ice Rise is an ice rise 11 miles (18 km) long and 2 to 4 kilometres wide, with an estimated area of 55 square kilometres (21 sq mi), located 17 kilometres (11 mi) off the northwest corner of Berkner Island in the Ronne Ice Shelf, Antarctica. The feature appears for the first time on a chart prepared at Ellsworth Station in 1957 by Captain Finn Ronne, U.S. Navy Reserve. The ice rise was subsequently noted in U.S. Earth Resources Technology Satellite imagery. It was named by the UK Antarctic Place-Names Committee for George E. Hemmen, Executive Secretary of the Scientific Committee on Antarctic Research in 1972; he served with the Falkland Islands Dependencies Survey as a meteorological observer at Admiralty Bay, 1952–53, and as Base Leader at Deception Island, 1953–54, and with the Royal Society Antarctic Expedition, 1956.
The Second German Antarctic Expedition of 1911–1913 was led by Wilhelm Filchner in the exploration ship Deutschland. Its principal objective was to determine whether the Antarctic continent comprised a single landmass rather than separated elements, and in particular whether the Weddell Sea and Ross Sea were connected by a strait. In addition, an extensive programme of scientific research was undertaken. The expedition failed to establish a land base, and the ship became beset in the Weddell Sea ice, drifting north for eight months before reaching open water. The expedition was marred by considerable disagreement and animosity among its participants, and broke up in disarray.
Edith Ronne Land was the unofficial name of that portion of Antarctica which is bordered by Palmer Land and Ellsworth Land to the West, Coats Land to the East, and the Filchner-Ronne Ice Shelf to the North. In December 2012, this region was officially named Queen Elizabeth Land by the British Government, which considers it part of the British Antarctic Territory.
Rutford Ice Stream is a major Antarctic ice stream, about 290 kilometres (180 mi) long and over 24 kilometres (15 mi) wide, which drains southeastward between the Sentinel Range, Ellsworth Mountains and Fletcher Ice Rise into the southwest part of Ronne Ice Shelf. Named by US-ACAN for geologist Robert Hoxie Rutford, a member of several USARP expeditions to Antarctica; leader of the University of Minnesota Ellsworth Mountains Party, 1963-1964. Rutford served as Director of the Division of Polar Programs, National Science Foundation, 1975-1977.
Fletcher Ice Rise, or Fletcher Promontory, is a large ice rise, 100 miles (160 km) long and 40 miles (64 km) wide, at the southwest side of the Ronne Ice Shelf, Antarctica. The feature is completely ice covered and rises between Rutford Ice Stream and Carlson Inlet. The ice rise was observed, photographed and roughly sketched by Lieutenant Ronald F. Carlson, U.S. Navy, in the course of a C-130 aircraft flight of December 14–15, 1961 from McMurdo Sound to this vicinity and returning. It was mapped in detail by the U.S. Geological Survey from Landsat imagery taken 1973–74, and was named by the Advisory Committee on Antarctic Names for Joseph O. Fletcher, director of the Office of Polar Programs, National Science Foundation, 1971–74.
Ellsworth Scientific Station was a permanent, all year-round originally American, then Argentine Antarctic scientific research station named after American polar explorer Lincoln Ellsworth. It was located on Gould Bay, on the Filchner Ice Shelf.
Gould Bay is a bay located at the junction of the Filchner Ice Shelf with the northeast corner of Berkner Island, in the southern Weddell Sea. It was discovered by the Ronne Antarctic Research Expedition, 1947–48, under the leadership of Commander Finn Ronne, U.S. Navy Reserve, who named this bay for Laurence M. Gould, geologist, geographer, and second in command of the Byrd Antarctic Expedition, 1928–30.
Raymond Effect is a flow effect in ice sheets, occurring at flow divides, which gives rise to disturbances in the stratigraphy, showing unusual arches or anticlines called Raymond Arches. The stratigraphy is detected by radio-echo sounding. The Raymond Effect arises from the unusual flow properties of ice, as its viscosity decreases with stress. It is of importance because it provides field evidence for the flow properties of ice. In addition, it permits dating of changes in ice flow and the establishment of changes in ice thickness. The effect was first predicted by Charles F. Raymond. Raymond Arches and the Raymond Effect have been observed at numerous other ice divides e.g. Siple Dome, Fletcher Ice Rise, Berkner Island, Roosevelt Island, and Korff Ice Rise.
Queen Elizabeth Land is a portion of mainland Antarctica named by the government of the United Kingdom and claimed as part of the British Antarctic Territory. Situated south of Weddell Sea and between longitudes 20°W and 80°W, stretching from Filchner-Ronne Ice Shelf to the South Pole. It is bordered by Zumberge Coast of Ellsworth Land to the West and by Hercules Inlet to the Northwest. To the Northeast, circle of latitude 82°S is the dividing line against Coats Land. The area of Queen Elizabeth Land was unnamed until 2012, though most of it was unofficially known as Edith Ronne Land in 1947–68 and includes areas claimed by the United Kingdom, Chile and Argentina.
A-38 was a large iceberg that split from the Filchner-Ronne Ice Shelf in Antarctica in October 1998. Soon after formation it split into two pieces, A-38A and A-38B, which drifted westwards on the Weddell Gyre. The icebergs moved north along the Antarctic Peninsula and reached its tip in February 2003. A-38A and A-38B increased speed in open sea and grounded in shallower waters to the east of South Georgia Island in December 2003. A-38A broke up into three pieces in March 2004 and drifted north where it decayed. A-38B split into two in April, with the eastern portion, now known as A-38G, drifting north and west to decay. The remainder of A-38B remained grounded, interfering with the foraging routes of seals and penguins in South Georgia, resulting in the deaths of their young. On 20 August 2004, A38-B broke into two, with the new portion drifting north and breaking up. The remainder of A-38B continued to break up through September 2004 and had completely decayed by 2005.
Filchner Station was a German research station in the Antarctic. Administered by the Alfred Wegener Institute for Polar and Marine Research, it was established in February 1982 on the Filchner–Ronne Ice Shelf. The first station in Antarctica to be mounted on jacks, the structure was raised each year to allow for the increase in height of the shelf by snowfall. It was also relocated around 1 kilometre (0.62 mi) southwards each year to account for drift of the ice shelf. In October 1998, Filchner Station was stranded on iceberg A-38 when it broke away from the ice shelf. Research operations were cancelled and an emergency salvage operation was carried out that removed the majority of the station by February 1999.