The Aleutian Basin is an

oceanic basin In hydrology, an oceanic basin (or ocean basin) is anywhere on Earth that is covered by seawater. Geologically, most of the ocean basins are large Structural basin, geologic basins that are below sea level. Most commonly the ocea ...

located beneath the southwestern

Bering Sea The Bering Sea ( , ; rus, Бе́рингово мо́ре, r=Béringovo móre, p=ˈbʲerʲɪnɡəvə ˈmorʲe) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasse ...

. While the northeastern half of the Bering Sea is situated over the North American Plate in relatively shallow waters, the Aleutian Basin comprises an oceanic plate, which is the remaining portion of the Kula Plate that was predominantly

subducted Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second plat ...

beneath the North American Plate.New Views of the U.S. Continental Margins (University of New Hampshire)
/ref> Subduction of the Kula Plate came to a halt following the formation of the

Aleutian Trench The Aleutian Trench (or Aleutian Trough) is an oceanic trench along a convergent plate boundary which runs along the southern coastline of Alaska and the Aleutian islands. The trench extends for from a triple junction in the west with the Ula ...

situated to its south. The remaining portion of the Kula Plate became attached to the North American Plate. This former subduction zone is now known as the Beringian Margin, which currently accommodates sixteen

submarine canyons A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to , from canyon flo ...

, including

Zhemchug Canyon Zhemchug Canyon (from the Russian жемчуг, "pearl") is an underwater canyon located in the Bering Sea between the Siberian and Alaskan coastlines. It is the deepest submarine canyon in the world with a vertical relief of 8,530 feet (2,6 ...

, recognized as the world's largest. The deep-water part of the Bering Sea is separated into the Commander Basin and Bowers basins by the submarine Shirshov Ridge and

Bowers Ridge The Bowers Ridge is located in the southern part of the Aleutian Basin. It extends over in an arc, starting in the southeast at the Aleutian Arc The Aleutian Arc is a large volcanic arc of islands extending from the Southwest tip of the U.S. ...

. The Commander Basin occupies the western part of the Bering Sea, with the Shirshov Ridge on its eastern border. The Shirshov Ridge extends 750 km southward from the Russian Olyutorskii Peninsula to connect with Bowers Ridge. The Bowers Ridge extends in the form of an arc over approximately 900 km from the

Aleutian Islands The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi language, Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before Alaska Purchase, 1867, the Catherine Archipelago—are a chain ...

Arc to the northwestern termination, where it meets Shirshov Ridge. This former

island arc Island arcs are long archipelago, chains of active volcanoes with intense earthquake, seismic activity found along convergent boundary, convergent plate tectonics, tectonic plate boundaries. Most island arcs originate on oceanic crust and have re ...

, Bowers Ridge, is a prominent semi-circular-shaped geological that meets the Aleutian arc and, together with the Aleutians, bounds Bowers Basin. Aleutian Basin Detail

The northern part of the Shirshov Ridge formed 95 My before the present. The ridge grows younger as it goes south, with the southern part of the Shirshov Ridge formed 33 My ago (Early Oligocene). Bowers Ridge was formed 30 My before the present (Late Oligocene).

References

{{coord, 57, N, 177, E, type:landmark_region:XP_dim:3000000, display=title Oceanic basins of the Pacific Ocean Landforms of the Bering Sea