Amerasia Basin

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Amerasia Basin is one of the two main basins of the Arctic Ocean, the other being the Eurasian Basin. It is roughly triangle-shaped and stretches from the Canadian Arctic Islands to the East Siberian Sea, and from Alaska to the Lomonosov Ridge. It includes several features: the Canada Basin, the Makarov Basin, the Podvodnikov Basin, the Alpha-Mendeleev Ridge, and the Chukchi Plateau.

The basin connects to the Pacific Ocean through the Bering Strait and to the North Atlantic Ocean via the Fram Strait and the Eurasia Basin. The surrounding continental shelf is very wide, up to about 550 kilometers. The basin’s average depth is about 3,950 meters, and it covers around 2.5 million square kilometers (970,000 square miles).

In terms of crust, the Canada Basin’s center is underlain by oceanic crust, with margins of extended or transitional crust. The Makarov and Podvodnikov basins may also have oceanic crust, or they could be highly extended continental crust with volcanic intrusions. The Alpha and Mendeleev ridges (the Alpha-Mendeleev Ridge) are mostly volcanic in origin, possibly with some extended crust underneath. The Chukchi Plateau is made of continental crust.

There are several ideas about how the Amerasia Basin formed. A popular one is the "windshield wiper" model, which suggests the Arctic Alaska-Chukotka terrane rotated counterclockwise away from the Canadian Arctic Islands during the Late Jurassic to Cretaceous, opening the basin at the expense of an extinct ocean called the South Anuyi Ocean. This model might explain the Canada Basin, but a full explanation for the whole Amerasia Basin is more complex.

The Alpha–Mendeleev Ridge is part of the High Arctic Large Igneous Province (HALIP), a big province of volcanic rocks in the Arctic. An Early Cretaceous dyke swarm covers a large area, and HALIP formation is linked to a mantle plume that may have caused regional plate movements, helping open the Amerasia Basin and rotating the AAC.