The Amerasia Basin, or Amerasian Basin, is one of the two major basins from which the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

can be subdivided (the other one being the

Eurasian Basin The Eurasian Basin, or Eurasia 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 Atla ...

). The triangular-shaped Amerasia Basin broadly extends from the

Canadian Arctic Islands The Arctic Archipelago, also known as the Canadian Arctic Archipelago, is an archipelago lying to the north of the Canadian continental mainland, excluding Greenland (an autonomous territory of Denmark). Situated in the northern extremity of ...

to the East Siberian Sea, and from

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...

to the

Lomonosov Ridge The Lomonosov Ridge (russian: Хребет Ломоносова, da, Lomonosovryggen) is an unusual underwater ridge of continental crust in the Arctic Ocean. It spans between the New Siberian Islands over the central part of the ocean to Elle ...

. The basin can be further subdivided based on bathymetric features; these include the

Canada Basin The Canada Basin is a deep oceanic basin within the Arctic Ocean. It is part of the Amerasian Basin and lies off the coast of Alaska and northwest Canada between the Chukchi Plateau north of Alaska and the Alpha Ridge north of Ellesmere Island ...

, the Makarov Basin, the Podvodnikov Basin, the Alpha-Mendeleev Ridge, and the

Chukchi Plateau The Chukchi Plateau or Chukchi Cap is a large subsea formation extending north from the Alaskan margin into the Arctic Ocean. The ridge is normally covered by ice year-round, and reaches an approximate bathymetric prominence of 3,400 m with i ...

. The Amerasia Basin is connected to the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

via the Bering Strait and to the North Atlantic Ocean via the Eurasia Basin and the

Fram Strait The Fram Strait is the passage between Greenland and Svalbard, located roughly between 77°N and 81°N latitudes and centered on the prime meridian. The Greenland and Norwegian Seas lie south of Fram Strait, while the Nansen Basin of the Arcti ...

. The continental shelf around the Amerasia Basin is very broad, averaging up to in width. The average depth of the Amerasia Basin is , and it covers . The

(with a maximum depth of ) 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 Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic ...

, 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

is made of

continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called '' sial'' be ...

. 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 The Arctic Alaska-Chukotka terrane (AAC) is a microcontinent that today encompasses the North Slope, Brooks Range, and Seward Peninsula of northern Alaska; the Chukotka Peninsula, New Siberia Islands, and Wrangel Island in eastern Siberia; and ...

(AAC) was rotated in a counter-clockwise motion, away from the

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 The High Arctic Large Igneous Province (HALIP) is a Cretaceous large igneous province in the Arctic. The region is divided into several smaller magmatic provinces. Svalbard, Franz Josef Land, Sverdrup Basin, Amerasian Basin, and northern Greenlan ...

(HALIP) which includes volcanic features offshore and onshore around the Arctic. An associated Early Cretaceous

dyke swarm A dike swarm (American spelling) or dyke swarm (British spelling) is a large geological structure consisting of a major group of parallel, linear, or radially oriented magmatic dikes intruded within continental crust or central volcanoes ...

covering at least has also been discovered. HALIP formation is related to the arrival of a

mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hot ...

, 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.

References

; Notes ; Sources * * *
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* {{Coord, 81, N, 160, E, dim:1000000, display=title Oceanic basins of the Arctic Ocean Abyssal plains