Eurasian Basin

The Eurasia Basin, or Eurasian Basin, is one of the two major basins into which the Arctic Basin of the Arctic Ocean is split by the Lomonosov Ridge (other being the Amerasia Basin). The Eurasia Basin may be seen as an extension of the North Atlantic Basin through Fram Strait. It is further split by the mid-ocean Gakkel Ridge into the Nansen Basin and the Amundsen Basin. The latter basin is the deepest one of the Arctic Ocean and the geographic North Pole is located there.

The Eurasia Basin is bounded by Greenland, the Lomonosov Ridge, and the shelves of the Laptev Sea, Kara Sea and Barents Sea. The maximum depth within the Eurasia Basin is reached at the Litke Deep with 5449 m depth.[1]

Today, the Gakkel Ridge is the site of some of the slowest seafloor spreading on the Earth, with 10 mm/yr near the Fram Strait and 6 mm/yr near the Laptev Sea. Initial opening of the Eurasia Basin is constrained by magnetic anomaly and geologic information to the Cenozoic: it was first created about 53 Million years ago by the spreading of the sea floor.[2]

Arctic Ocean bathymetric features
Main bathymetric features of the Arctic Ocean

References

  1. ^ Physical characteristics of the Arctic
  2. ^ "Plate Tectonics Model for the Evolution of the Arctic", Geology, vol. 2, Issue 8, p.377 (1974) doi:10.1130/0091-7613(1974)2<377:PTMFTE>2.0.CO;2

Coordinates: 83°N 50°W / 83°N 50°W

Amerasia Basin

The Amerasia Basin, or Amerasian Basin, is one of the two major basins from which the Arctic Ocean can be subdivided (the other one being the Eurasian Basin). The triangular-shaped Amerasia Basin broadly extends from the Canadian Arctic Islands to the East Siberian Sea, and from Alaska to the Lomonosov Ridge. The basin can be further subdivided based on bathymetric features; these include the Canada Basin, the Makarov Basin, the Podvodnikov Basin, the Alpha-Mendeleev Ridge, and the Chukchi Plateau.

The Amerasia Basin is connected to the Pacific Ocean via the Bering Strait and to the North Atlantic Ocean via the Eurasia Basin and the Fram Strait. The continental shelf around the Amerasia Basin is very broad, averaging up to 342 mi (550 km) in width. The average depth of the Amerasia Basin is 12,960 ft (3,950 m), and it covers 2,500,000 km2 (970,000 sq mi).

The Canada Basin (with a maximum depth of 4,000 m (13,000 ft)) is underlain by oceanic crust at its centre, as well as extended continental crust and transitional-type crust around its margins. The Makarov and Podvodnikov basins, may include oceanic crust, though have also been suggested to be highly extended continental crust or intruded by volcanics. The Alpha and Mendeleev ridges (also collectively referred to as the Alpha-Mendeleev Ridge) are considered to be predominantly volcanic in origin, possibly with a component of extended continental crust underneath. The Chukchi Plateau is made of continental crust.Many scenarios have been proposed for the opening of the Amerasia Basin. The most popular, the "windshield wiper" model, proposes that the Arctic Alaska-Chukotka terrane (AAC) was rotated in a counter-clockwise motion, away from the Canadian Arctic Islands during the Late Jurassic–Cretaceous in one or several stages. Its opening was at the expense of an extinct ocean called the South Anuyi Ocean. It is possible that the windshield model can explain the opening of the Canada Basin, but that a more complex pattern of events is required to explain the structure of the Amerasia Basin as a whole.The Alpha–Mendeleev Ridge forms part of the Cretaceous High Arctic Large Igneous Province (HALIP) which includes volcanic features offshore and onshore around the Arctic. An associated Early Cretaceous dyke swarm covering at least 350 km × 800 km (220 mi × 500 mi) has also been discovered. HALIP formation is related to the arrival of a mantle plume, possibly centered on the southern end of the Alpha Ridge. The plume arrival may have resulted in a regional plate reorganization event, including the opening of the Amerasia Basin and the rotation of the AAC.

Amundsen Basin

The Amundsen Basin, with depths up to 4.4 km, is the deepest abyssal plain in the Arctic Ocean. The Amundsen Basin is embraced by the Lomonosov Ridge (from 81°N 140°E to 80°N 40°W) and the Gakkel Ridge (from 81°N 120°E to 85°N 10°E). It is named after the polar researcher Roald Amundsen. Together with the Nansen Basin, the Amundsen Basin is often summarized as Eurasian Basin.

The Russian-American cooperation Nansen and Amundsen Basin Observational System (NABOS) aims "to provide a quantitative observationally based assessment of circulation, water mass transformations, and transformation mechanisms in the Eurasian and Canadian Basins of the Arctic Ocean".

Arctic Basin

The Arctic Basin (also North Polar Basin) is an oceanic basin in the Arctic Ocean, consisting of two main parts separated by the Lomonosov Ridge, a mid-ocean ridge running between north Greenland and the New Siberian Islands. The basin is bordered by the continental shelves of Eurasia and North America.

The Eurasian Basin (also Norwegian Basin) consists of the Nansen Basin (formerly: Fram Basin) and the Amundsen Basin

The Amerasian Basin consists of the Canada Basin and the Makarov Basin

Arctic Ocean

The Arctic Ocean is the smallest and shallowest of the world's five major oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea or simply the Arctic Sea, classifying it a mediterranean sea or an estuary of the Atlantic Ocean. It is also seen as the northernmost part of the all-encompassing World Ocean.

Located mostly in the Arctic north polar region in the middle of the Northern Hemisphere, the Arctic Ocean is almost completely surrounded by Eurasia and North America. It is partly covered by sea ice throughout the year and almost completely in winter. The Arctic Ocean's surface temperature and salinity vary seasonally as the ice cover melts and freezes; its salinity is the lowest on average of the five major oceans, due to low evaporation, heavy fresh water inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of the ice has been quoted at 50%. The US National Snow and Ice Data Center (NSIDC) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years.

Atlantic Ocean

The Atlantic Ocean is the second largest of the world's oceans, with an area of about 106,460,000 square kilometers (41,100,000 square miles). It covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. It separates the "Old World" from the "New World".

The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and the Americas to the west. As one component of the interconnected global ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Equatorial Counter Current subdivides it into the North Atlantic Ocean and the South Atlantic Ocean at about 8°N.Scientific explorations of the Atlantic include the Challenger expedition, the German Meteor expedition, Columbia University's Lamont-Doherty Earth Observatory and the United States Navy Hydrographic Office.

Extreme points of the Arctic

This is a list of the extreme points of the Arctic, the points of Arctic lands that are farther to the north than any other location classified by continent and country, latitude and longitude, and distance to the North Pole. The list is sorted from north to south.

Extremes on Earth

This article describes extreme locations on Earth. Entries listed in bold are Earth-wide extremes.

Gakkel Ridge

The Gakkel Ridge (formerly known as the Nansen Cordillera and Arctic Mid-Ocean Ridge) is a mid-oceanic ridge, a divergent tectonic plate boundary between the North American Plate and the Eurasian Plate. It is located in the Eurasian Basin of the Arctic Ocean, between Greenland and Siberia, and has a length of about 1,800 kilometers. Geologically, it connects the northern end of the Mid-Atlantic Ridge with the Laptev Sea Rift.

The existence and approximate location of the Gakkel Ridge were predicted by Soviet polar explorer Yakov Yakovlevich Gakkel, and confirmed on Soviet expeditions in the Arctic around 1950. The Ridge is named after him, and the name was recognized in April 1987 by SCUFN (under that body's old name, the Sub-Committee on Geographical Names and Nomenclature of Ocean Bottom Features).The ridge is the slowest known spreading ridge on earth, with a rate of less than one centimeter per year. Until 1999, it was believed to be non-volcanic; that year, scientists operating from a nuclear submarine discovered active volcanoes along it. In 2001 two research icebreakers, the German Polarstern and the American Healy, with several groups of scientists, cruised to the Gakkel Ridge to explore it and collect petrological samples. Among other discoveries, this expedition found evidence of hydrothermal vents. In 2007, Woods Hole Oceanographic Institution conducted the "Arctic Gakkel Vents Expedition" (AGAVE), which made some unanticipated discoveries, including the unconsolidated fragmented pyroclastic volcanic deposits that cover the axial valley of the ridge (whose area is greater than 10 km2). These suggest volatile substances in concentrations ten times those in the magmas of normal mid-ocean ridges. Using "free-swimming" robotic submersibles on the Gakkel ridge, the AGAVE expedition also discovered what they called "bizarre 'mats' of microbial communities containing a half dozen or more new species".The Gakkel ridge is remarkable in that is not offset by any transform faults. The ridge does have segments with variable orientation and varying degrees of volcanism: the Western Volcanic Zone From the Lena trough, 7° W, to 3° E longitude), the Sparsely Magmatic Zone (from 3° E to 29° E longitude), and the Eastern Magmatic Zone (from 29° E to 89°E) . The gaps of volcanic activity imply very cold crust and mantle, probably related to the very low spreading rate, but it is not yet known why some parts of the ridge are more magmatic than others. Some earthquakes have been detected from the mantle, below the crust, which is very unusual for a mid-ocean ridge . It confirms that the mantle and crust of Gakkel ridge, like some segments of the Southwest Indian Ridge, are very cold.

Lincoln Sea

Lincoln Sea (French: Mer de Lincoln; Danish: Lincolnhavet) is a body of water in the Arctic Ocean, stretching from Cape Columbia, Canada, in the west to Cape Morris Jesup, Greenland, in the east. The northern limit is defined as the great circle line between those two headlands. It is covered with sea ice throughout the year, the thickest sea ice in the Arctic Ocean, which can be up to 15 m (49 ft) thick. Water depths range from 100 m (330 ft) to 300 m (980 ft). Water and ice from Lincoln Sea empty into Robeson Channel, the northernmost part of Nares Strait, most of the time.

The sea was named after Robert Todd Lincoln, then United States Secretary of War, on Adolphus W. Greely's 1881–1884 Arctic expedition into Lady Franklin Bay.Alert, the northernmost station of Canada, is the only populated place on the shore of Lincoln Sea.

The body of water to the east of Lincoln Sea (east of Cape Morris Jesup) is Wandel Sea.

List of submarine topographical features

This is a list of submarine topographical features, oceanic landforms and topographic elements.

Litke Deep

Litke Deep (Russian: Жолоб Ли́тке) is an oceanic trench in the Arctic Ocean. It is the deepest known point in the Arctic Ocean. It is the 20th deepest oceanic trench in the world.

Lomonosov Ridge

The Lomonosov Ridge (Russian: Хребет Ломоносова, Danish: Lomonosovryggen) is an unusual underwater ridge of continental crust in the Arctic Ocean. It spans 1,800 kilometres (1,100 mi) between the New Siberian Islands over the central part of the ocean to Ellesmere Island of the Canadian Arctic Archipelago. The ridge divides the Arctic Basin into the Eurasian Basin and the Amerasian Basin. The width of the Lomonosov Ridge varies from 60 to 200 kilometres (37 to 124 mi). It rises 3,300 to 3,700 metres (10,800 to 12,100 ft) above the 4,200-metre (13,800 ft) deep seabed. The minimum depth of the ocean above the ridge is less than 400 metres (1,300 ft). Slopes of the ridge are relatively steep, broken up by canyons, and covered with layers of silt.

The Lomonosov Ridge was first discovered by the Soviet high-latitude expeditions in 1948 and is named after Mikhail Lomonosov. The name was approved by the GEBCO Sub-Committee on Undersea Feature Names (SCUFN).

Nansen Basin

The Nansen Basin (also Central Basin, formerly Fram Basin) is an abyssal plain with water-depths of around 3 km in the Arctic Ocean and (together with the deeper Amundsen Basin) part of the Eurasian Basin. It is named after Fridtjof Nansen. The Nansen Basin is bounded by the Gakkel Ridge on the one side and by the Barents Sea continental shelf on the other.The lowest point of the Arctic Ocean lies within the Nansen Basin and has a depth of 4,665 m. The Barents Abyssal Plain is located at the center of the Fram Basin.

Siberian Shelf

The Siberian Shelf, one of the Arctic Ocean coastal shelves (such as the Milne Ice Shelf), is the largest continental shelf of the Earth, a part of the continental shelf of Russia. It extends from the continent of Eurasia in the general area of North Siberia (hence the name) into the Arctic Ocean. It stretches to 1,500 kilometers (930 mi) offshore. It is relatively shallow, with average depth of 100 m. A number of islands are within the shelf, including the Wrangel Island, Novaya Zemlya, and the New Siberian Islands. It is encompassed by the Kara Sea, Laptev Sea, and East Siberian Sea, and respectively subdivided into the Kara Shelf, the Laptov Shelf and the East Siberian Shelf.

Eastwards it merges into the Chukchi Shelf (of the Chukchi Sea) shared by Eurasia and North America (i.e., by Russia and the United States).

Westwards it merges into the Barents Shelf of the Barents Sea.

Also, the New Siberian Islands and the New Siberian Rift Basin define the 'New Siberian Shelf.'

According to the split of the high Arctic by the Lomonosov mid-ocean ridge into the Eurasian Basin and Amerasian Basin, the Siberian Shelf is split between the Eurasian Shelf and the Amerasian Shelf.

Transpolar Drift Stream

The Transpolar Drift Stream is a major ocean current of the Arctic Ocean, transporting sea ice from the Laptev Sea and the East Siberian Sea towards Fram Strait. Drift experiments with ships like Fram or Tara showed that the drift takes between two and four years.

In 1937, Pyotr Shirshov at the Soviet drift ice station North Pole-1 described this drift. The stream conveys water in roughly two major routes to the northern Atlantic Ocean at a rate of about 1.5 miles (2.4 km) per day. Primarily wind-driven, it flows roughly from the northern coast of Russia and Alaska, sometimes curving toward the Beaufort Sea before exiting to the Atlantic Ocean. It has been cited as a major factor in the North Atlantic Oscillation and Arctic oscillation atmospheric changes. The drift typically takes one of two paths before exiting into the northern Atlantic Ocean.

On decadal and longer timescales, the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) indices affect the flow pattern of the transpolar drift stream. During times of positive NAO (NAO+) and positive AO (AO+), there is a weak Arctic high and the associated surface winds produce a cyclonic (anti-clockwise) ice drift motion in eastern Arctic Ocean. In this case, the drift flows from the Laptev Sea towards the Beaufort Sea before exiting the Arctic Ocean through the Fram Strait. Conversely, during periods of NAO- and AO-, there is a strong Arctic high and ice motion flows in an anticyclonic (clockwise) motion in the Eurasian Basin. In this phase, the drift flows directly from the Laptev Sea through the Fram Strait.

West Spitsbergen Current

The West Spitsbergen Current (WSC) is a warm, salty current that runs poleward just west of Spitsbergen, (formerly called West Spitsbergen), in the Arctic Ocean. The WSC branches off the Norwegian Atlantic Current in the Norwegian Sea. The WSC is of importance because it drives warm and salty Atlantic Water into the interior Arctic. The warm and salty WSC flows north through the eastern side of Fram Strait, while the East Greenland Current (EGC) flows south through the western side of Fram Strait. The EGC is characterized by being very cold and low in salinity, but above all else it is a major exporter of Arctic sea ice. Thus, the EGC combined with the warm WSC makes the Fram Strait the northernmost ocean area having ice-free conditions throughout the year in all of the global ocean.

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