The geography of Antarctica is dominated by its south polar location and, thus, by ice. The Antarctic continent, located in the Earth's southern hemisphere, is centered asymmetrically around the South Pole and largely south of the Antarctic Circle. It is washed by the Southern (or Antarctic) Ocean or, depending on definition, the southern Pacific, Atlantic, and Indian Oceans. It has an area of more than 14 million km².
Some 98% of Antarctica is covered by the Antarctic ice sheet, the world's largest ice sheet and also its largest reservoir of fresh water. Averaging at least 1.6 km thick, the ice is so massive that it has depressed the continental bedrock in some areas more than 2.5 km below sea level; subglacial lakes of liquid water also occur (e.g., Lake Vostok). Ice shelves and rises populate the ice sheet on the periphery.
In September 2018, researchers at the National Geospatial-Intelligence Agency released a high resolution terrain map (detail down to the size of a car, and less in some areas) of Antarctica, named the "Reference Elevation Model of Antarctica" (REMA).
|Geography of Antarctica|
|Area||Ranked 2nd (unofficially)|
|• Total||14,000,000 km2 (5,400,000 sq mi)|
|Coastline||17,968 km (11,165 mi)|
|Borders||No land boundaries|
|Highest point||Vinson Massif, 4,897 m (16,066 ft)|
|Lowest point||Bentley Subglacial Trench, −2,555 m (−8,382.5 ft)|
|Longest river||Onyx River, 25 km|
|Largest lake||Lake Vostok, 26,000 sq m (est.)|
|Climate||subantarctic to antarctic|
|Terrain||ice and barren rock|
|Natural Resources||krill, fin fish, crab|
|Natural Hazards||high winds, blizzards, cyclonic storms, volcanism|
|Environmental Issues||depleting ozone layer, rising sea level|
Physically, Antarctica is divided in two by Transantarctic Mountains close to the neck between the Ross Sea and the Weddell Sea. Western Antarctica and Eastern Antarctica correspond roughly to the eastern and western hemispheres relative to the Greenwich meridian. This usage has been regarded as Eurocentric by some, and the alternative terms Lesser Antarctica and Greater Antarctica (respectively) are sometimes preferred.
Lesser Antarctica is covered by the West Antarctic Ice Sheet. There has been some concern about this ice sheet, because there is a small chance that it will collapse. If it does, ocean levels would rise by a few metres in a very short period of time.
Volcanoes that occur underneath glacial ice sheets are known by the term "Glaciovolcanism", or subglacial volcanoes. An article published in 2017 claims that researchers from Edinburgh University recently discovered 91 new volcanoes below the Antarctic ice sheet, adding to the 47 volcanoes that were already known. As of today, there have been 138 possible volcanoes identified in West Antarctica. There is limited knowledge about West Antarctic Volcanoes due to the presence of the West Antarctic Ice Sheet, which heavily covers the West Antarctic Rift System -- a likely hub for volcanic activity. Researchers find it difficult to properly identify volcanic activity due to the comprehensive ice covering.
East Antarctica is significantly larger than West Antarctica, and similarly remains widely unexplored in terms of its volcanic potential. While there are some indications that there is volcanic activity under the East Antarctic Ice Sheet, there is not a significant amount of present information on the subject.
Mount Erebus is one of the most notable sites in the study of Antarctic Volcanism, in that it is the southernmost historically active volcanic site on the planet.
Deception Island is another active Antarctic volcano. It is one of the most protected areas in the Antarctic, given its situation between the South Shetland Islands and the Antarctic Peninsula. As the most active volcano in the Antarctic peninsula, it has been studied closely since its initial discovery in 1820.
There are four volcanoes on the mainland of Antarctica that are considered to be active on the basis of observed fumarolic activity or "recent" tephra deposits: Mount Melbourne (2,730 m) (74°21'S., 164°42'E.), a stratovolcano; Mount Berlin (3,500 m) (76°03'S., 135°52'W.), a stratovolcano; Mount Kauffman (2,365 m) (75°37'S., 132°25'W.), a stratovolcano; and Mount Hampton (3,325 m) (76°29'S., 125°48'W.), a volcanic caldera.
Several volcanoes on offshore islands have records of historic activity. Mount Erebus (3,795 m), a stratovolcano on Ross Island with 10 known eruptions and 1 suspected eruption. On the opposite side of the continent, Deception Island (62°57'S., 60°38'W.), a volcanic caldera with 10 known and 4 suspected eruptions, have been the most active. Buckle Island in the Balleny Islands (66°50'S., 163°12'E.), Penguin Island (62°06'S., 57°54'W.), Paulet Island (63°35'S., 55°47'W.), and Lindenberg Island (64°55'S., 59°40'W.) are also considered to be active. In 2017, the researchers of Edinburgh University discovered 91 underwater volcanoes under West Antarctica.
The definition of Glaciovolcanism is “the interactions of magma with ice in all its forms, including snow, firn and any meltwater.” It defines a special field of volcanic that is specifically centered around ice and ice melt. This field of science is less than 100 years old, and thus continuously makes new discoveries. Glaciovolcanism is characterized by three kinds of eruptions: sub-glacial eruptions, supraglacial volcanism, and ice-marginal volcanism.
The study of glaciovolcanism is vital to the understanding of ice sheet formation. It is also a valuable tool to predict volcanic hazards, such as the ash hazard following the Eyjafjallajökull eruption in Iceland.
The Marie Byrd Land is an incredibly large portion of West Antarctica, consisting of the Area below the Antarctic Peninsula. The Marie Byrd land is a large formation of volcanic rock, characterized by 18 exposed and subglacial volcanoes. 16 of the 18 volcanoes are entirely covered by the antarctic ice sheet. There have been no eruptions recorded from any of the volcanoes in this area, however scientists believe that some of the volcanoes may be potentially active.
Scientists and researchers debate whether or not the 138 identified possible volcanoes are active or dormant. It is very hard to definitively say, given that many of these volcanic structures are buried underneath several kilometers of ice. However, ash layers within the West Antarctic Ice Sheet, as well as deformations in the ice surface indicate that the West Antarctic Rift System could be active and contain erupting volcanoes. Additionally, seismic activity in the region hints at magma movement beneath the crust, a sign of volcanic activity. Despite this, however, there is not yet definitive evidence of presently active volcanoes.
Subglacial volcanism is often characterized by ice melt and subglaical water. Though there are other sources of subglacial water, such as geothermal heat, it almost always is a condition of volcanism. Scientists remain uncertain about the presence of water underneath the West Antarctic Ice Sheet, with some claiming to have found evidence indicating the existence.
In West Antarctica's Marie Byrd Land, volcanoes are typically composed of alkaline and basaltic lava. Sometimes, the volcanoes are entirely basaltic in composition. Due to the geographic similarity of the Marie Byrd Land, it is believed that the volcanoes in the West African Rift System are also composed of basalt.
Above-ice basaltic volcanoes, also known as subaerial basaltic volcanoes, generally form in tall, broad cone shapes. Since they are formed from repeated piling of liquid magma sourced from the center, they spread widely and grow upwards relatively slowly. However, West Antarctic Volcanoes form underneath ice sheets, and are thus categorized as subglacial volcanoes. Subglacial volcanoes that are monogenetic are far more narrow, steeper, flat topped structures. Polygenetic subglacial volcanoes have a wider variety of shapes and sizes due to being made up of many different eruptions. Often, they look more cone shaped, like statovolcanoes.
Little has been studied about the implications of volcanic ash from eruptions within the Antarctic Circle. It is likely that an eruption at lower latitudes would cause global health and aviation hazards due to ash disbursement. The clockwise air circulation around the low pressure system at the South Pole forces air upwards, hypothetically sending ash upwards towards the Stratospheric jet streams, and thus quickly dispersing it throughout the globe.
Recently, in 2017, a study found evidence of subglacial volcanic activity within the West Antarctic Ice Sheet. This activity poses a threat to the stability of the Ice Sheet, as volcanic activity leads to increased melting. This could possibly plunge the West Antarctic Ice Sheet into a positive feedback loop of rising temperatures and increased melting.
There are three vast canyons that run for hundreds of kilometers, cutting through tall mountains. None of the canyons are visible at the snow-covered surface of the continent since they are buried under hundreds of meters of ice. The largest of the canyons is called Foundation Trough and is over 350km long and 35km wide. The Patuxent Trough is more than 300km long and over 15km wide, while the Offset Rift Basin is 150km long and 30km wide. These three troughs all lie under and cross the so-called "ice divide" - the high ice ridge that runs all the way from the South Pole out towards the coast of West Antarctica.
West Antarctica is the smaller part of the continent, (50° – 180°W), divided into:
Larger ice shelves are:
For all ice shelves see List of Antarctic ice shelves.
For a list of all Antarctic islands see List of Antarctic and sub-Antarctic islands.
Larger ice shelves are:
For all ice shelves see List of Antarctic ice shelves.
For a list of all Antarctic islands see List of Antarctic and sub-Antarctic islands.
Seven nations have made official Territorial claims in Antarctica.
The 70th parallel south is a circle of latitude that is 70 degrees south of the Earth's equatorial plane in the Antarctic. The parallel passes through the Southern Ocean and Antarctica.80th parallel south
The 80th parallel south is a circle of latitude that is 80 degrees south of the Earth's equatorial plane.
The parallel passes only through Antarctica and Antarctic ice shelves.Advisory Committee on Antarctic Names
The Advisory Committee on Antarctic Names (ACAN or US-ACAN) is an advisory committee of the United States Board on Geographic Names responsible for recommending names for features in Antarctica. The United States does not recognise territorial boundaries within Antarctica, so ACAN will assign names to features anywhere within the continent, in consultation with other national nomenclatural bodies where appropriate.
ACAN has a published policy on naming, based on priority of application, appropriateness, and the extent to which usage has become established.Antarctic
The Antarctic (US English , UK English or and or ) is a polar region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately 32 to 48 km (20 to 30 mi) wide varying in latitude seasonally. The region covers some 20 percent of the Southern Hemisphere, of which 5.5 percent (14 million km2) is the surface area of the Antarctic continent itself. All of the land and ice shelves south of 60°S latitude are administered under the Antarctic Treaty System. Biogeographically, the Antarctic ecozone is one of eight ecozones of the Earth's land surface.Antarctic Circle
The Antarctic Circle is the most southerly of the five major circles of latitude that mark maps of the Earth. The region south of this circle is known as the Antarctic, and the zone immediately to the north is called the Southern Temperate Zone. South of the Antarctic Circle, the sun is above the horizon for 24 continuous hours at least once per year (and therefore visible at midnight) and the centre of the sun is below the horizon for 24 continuous hours at least once per year (and therefore not visible at noon); this is also true within the equivalent polar circle in the Northern Hemisphere, the Arctic Circle.
The position of the Antarctic Circle is not fixed and currently runs 66°33′47.8″ south of the Equator. Its latitude depends on the Earth's axial tilt, which fluctuates within a margin of more than 2° over a 41,000-year period, due to tidal forces resulting from the orbit of the Moon. Consequently, the Antarctic Circle is currently drifting southwards at a speed of about 15 m (49 ft) per year.East Antarctica
East Antarctica, also called Greater Antarctica, constitutes the majority (two-thirds) of the Antarctic continent, lying on the Indian Ocean side of the continent, separated from West Antarctica by the Transantarctic Mountains. It lies almost entirely within the Eastern Hemisphere and its name has been accepted for more than a century. It is generally higher than West Antarctica and includes the Gamburtsev Mountain Range in the centre.
Apart from small areas of the coast, East Antarctica is permanently covered by ice. The only terrestrial plant life is lichens, mosses and algae clinging to rocks, and there are a limited range of invertebrates including nematodes, springtails, mites and midges. The coasts are the breeding ground for various seabirds and penguins, and the leopard seal, Weddell seal, elephant seal, crabeater seal and Ross seal breed on the surrounding pack ice in summer.Extreme points of Antarctica
This is a list of extreme points in Antarctica.French Southern and Antarctic Lands
The French Southern and Antarctic Lands (French: Terres australes et antarctiques françaises, TAAF) is an overseas territory (French: Territoire d'outre-mer or TOM) of France. It consists of:
Kerguelen Islands (Archipel des Kerguelen), a group of volcanic islands in the southern Indian Ocean, southeast of Africa, approximately equidistant between Africa, Antarctica and Australia;
St. Paul and Amsterdam islands (Îles Saint Paul et Amsterdam), a group to the north of Kerguelen;
Crozet Islands (Îles Crozet), a group in the southern Indian Ocean, south of Madagascar;
Adélie Land (Terre Adélie), the French claim on the continent of Antarctica;
the Scattered Islands (Îles Éparses), a dispersed group of islands around the coast of Madagascar.The territory is sometimes referred to as the French Southern Lands (French: Terres australes françaises) or French Southern Territories, usually to emphasize non-recognition of French sovereignty over Adélie Land as part of the Antarctic Treaty system.
Approximately 150 (in the winter) to 310 (in the summer) persons live in the French Southern and Antarctic Lands but they are only military personnel, officials, scientific researchers and support staff. The territory has legally no permanent civilian population.On July 5, 2019, the French Austral Lands and Seas were inscribed as a UNESCO World Heritage Site.Fuchs Medal
The Fuchs Medal is a medal awarded by The British Antarctic Survey for "Outstanding devotion to the British Antarctic Survey's interests, beyond the call of normal duty, by men or women who are or were members of the Survey, or closely connected with its work."Iceberg B-15
Iceberg B-15 was the world's largest recorded iceberg. It measured around 295 kilometres (183 mi) long and 37 kilometres (23 mi) wide, with a surface area of 11,000 square kilometres (4,200 sq mi)—larger than the whole island of Jamaica. Calved from the Ross Ice Shelf of Antarctica in March 2000, Iceberg B-15 broke up into smaller icebergs, the largest of which was named Iceberg B-15A. In 2003, B-15A drifted away from Ross Island into the Ross Sea and headed north, eventually breaking up into several smaller icebergs in October 2005. As of 2018, a large piece of the original iceberg was steadily moving northward, located between the Falkland Islands and South Georgia Island.Kaiser Wilhelm II Land
Kaiser Wilhelm II Land is a part of Antarctica lying between Cape Penck at 87° 43'E and Cape Filchner at 91° 54'E, and is claimed as part of the Australian Antarctic Territory, a claim not universally recognized.
The area was discovered on 22 February 1902, during the Gauss expedition of 1901–1903 led by Arctic veteran and geologist Erich von Drygalski. Drygalski named it after Kaiser Wilhelm II who had funded the expedition with 1.2 million Goldmarks.
Also discovered was the Gaussberg, a 370-metre-high (1,210 ft) extinct volcano named after mathematician and physicist Carl Friedrich Gauss.Polar regions of Earth
The polar regions, also called the frigid zones, of Earth are the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitudes are dominated by Earth's polar ice caps: the northern resting on the Arctic Ocean and the southern on the continent of Antarctica.Pole of Cold
The Poles of Cold are the places in the southern and northern hemispheres where the lowest air temperatures have been recorded.Pole of inaccessibility
A pole of inaccessibility with respect to a geographical criterion of inaccessibility marks a location that is the most challenging to reach according to that criterion. Often it refers to the most distant point from the coastline, implying a maximum degree of continentality or oceanity. In these cases, pole of inaccessibility can be defined as the center of the largest circle that can be drawn within an area of interest without encountering a coast. Where a coast is imprecisely defined, the pole will be similarly imprecise.South Magnetic Pole
The South Magnetic Pole is the wandering point on Earth's Southern Hemisphere where the geomagnetic field lines are directed vertically upwards. It should not be confused with the South Geomagnetic Pole described later.
For historical reasons, the "end" of a freely hanging magnet that points (roughly) north is itself called the "north pole" of the magnet, and the other end, pointing south, is called the magnet's "south pole". Because opposite poles attract, Earth's South Magnetic Pole is physically actually a magnetic north pole (see also North Magnetic Pole § Polarity).
The South Magnetic Pole is constantly shifting due to changes in Earth's magnetic field.
As of 2005 it was calculated to lie at 64°31′48″S 137°51′36″E, placing it off the coast of Antarctica, between Adélie Land and Wilkes Land. In 2015 it lay at 64.28°S 136.59°E / -64.28; 136.59 (est). That point lies outside the Antarctic Circle. Due to polar drift, the pole is moving northwest by about 10 to 15 kilometres (6 to 9 mi) per year. Its current distance from the actual Geographic South Pole is approximately 2,860 km (1,780 mi). The nearest permanent science station is Dumont d'Urville Station.South Pole
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of Earth and lies on the opposite side of Earth from the North Pole.
Situated on the continent of Antarctica, it is the site of the United States Amundsen–Scott South Pole Station, which was established in 1956 and has been permanently staffed since that year. The Geographic South Pole is distinct from the South Magnetic Pole, the position of which is defined based on Earth's magnetic field. The South Pole is at the center of the Southern Hemisphere.Subantarctic
The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and Pacific Ocean, especially those situated north of the Antarctic Convergence. Subantarctic glaciers are, by definition, located on islands within the subantarctic region. All glaciers located on the continent of Antarctica are by definition considered to be Antarctic glaciers.West Antarctica
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 (partly covered by the Ross Ice Shelf), and the Weddell Sea (largely covered by the Filchner-Ronne Ice Shelf). It may be considered a giant peninsula stretching from the South Pole towards the tip of South America.
West Antarctica is largely covered by the Antarctic ice sheet, but there have been signs that climate change is having some effect and that this ice sheet may have started to shrink slightly. The coasts of the Antarctic Peninsula are the only parts of West Antarctica that become (in summer) ice-free. These constitute the Marielandia Antarctic tundra and have the warmest climate in Antarctica. The rocks are clad in mosses and lichens that can cope with the intense cold of winter and the short growing-season.
Geography of Antarctica