Aleutian Basin

Last updated
Map of the Bering Sea, with the Aleutian Basin clearly discernable here in the southwest portion of the sea. LA2-Bering-Sea-UTM-zones.png
Map of the Bering Sea, with the Aleutian Basin clearly discernable here in the southwest portion of the sea.

The Aleutian Basin is an oceanic basin located beneath the southwestern Bering Sea. 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 beneath the North American Plate. [1]

Subduction of the Kula Plate came to a halt following the formation of the Aleutian Trench 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, including Zhemchug Canyon, recognized as the world's largest. [1]

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 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 Arc to the northwestern termination, where it meets Shirshov Ridge. This former island arc, Bowers Ridge, is a prominent semi-circular-shaped geological that meets the Aleutian arc and, together with the Aleutians, bounds Bowers Basin. [2]

Aleutian Basin features. Aleutian Basin Detail.jpg
Aleutian Basin features.

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). [2]

Related Research Articles

<span class="mw-page-title-main">Bering Sea</span> Sea of the northern Pacific Ocean off the coast of Alaska and Russia

The Bering Sea is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and the Americas. It comprises a deep water basin, which then rises through a narrow slope into the shallower water above the continental shelves. The Bering Sea is named after Vitus Bering, a Danish navigator in Russian service, who, in 1728, was the first European to systematically explore it, sailing from the Pacific Ocean northward to the Arctic Ocean.

<span class="mw-page-title-main">Oceanic trench</span> Long and narrow depressions of the sea floor

Oceanic trenches are prominent, long, narrow topographic depressions of the ocean floor. They are typically 50 to 100 kilometers wide and 3 to 4 km below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about 50,000 km (31,000 mi) of oceanic trenches worldwide, mostly around the Pacific Ocean, but also in the eastern Indian Ocean and a few other locations. The greatest ocean depth measured is in the Challenger Deep of the Mariana Trench, at a depth of 10,920 m (35,830 ft) below sea level.

Obduction is a geological process whereby denser oceanic crust is scraped off a descending ocean plate at a convergent plate boundary and thrust on top of an adjacent plate. When oceanic and continental plates converge, normally the denser oceanic crust sinks under the continental crust in the process of subduction. Obduction, which is less common, normally occurs in plate collisions at orogenic belts or back-arc basins.

<span class="mw-page-title-main">Coast Mountains</span> Mountain range in Canada and the United States

The Coast Mountains are a major mountain range in the Pacific Coast Ranges of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbia south to the Fraser River. The mountain range's name derives from its proximity to the sea coast, and it is often referred to as the Coast Range. The range includes volcanic and non-volcanic mountains and the extensive ice fields of the Pacific and Boundary Ranges, and the northern end of the volcanic system known as the Cascade Volcanoes. The Coast Mountains are part of a larger mountain system called the Pacific Coast Ranges or the Pacific Mountain System, which includes the Cascade Range, the Insular Mountains, the Olympic Mountains, the Oregon Coast Range, the California Coast Ranges, the Saint Elias Mountains and the Chugach Mountains. The Coast Mountains are also part of the American Cordillera—a Spanish term for an extensive chain of mountain ranges—that consists of an almost continuous sequence of mountain ranges that form the western backbone of North America, Central America, South America and Antarctica.

<span class="mw-page-title-main">Island arc</span> Arc-shaped archipelago formed by intense seismic activity of long chains of active volcanoes

Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle along the subduction zone. They are the principal way by which continental growth is achieved.

<span class="mw-page-title-main">Scotia Plate</span> Minor oceanic tectonic plate between the South American and Antarctic Plates

The Scotia Plate is a tectonic plate on the edge of the South Atlantic and Southern oceans. Thought to have formed during the early Eocene with the opening of the Drake Passage that separates South America from Antarctica, it is a minor plate whose movement is largely controlled by the two major plates that surround it: the South American Plate and the Antarctic Plate. The Scotia Plate takes its name from the steam yacht Scotia of the Scottish National Antarctic Expedition (1902–04), the expedition that made the first bathymetric study of the region.

<span class="mw-page-title-main">Kula Plate</span> Former oceanic tectonic plate

The Kula Plate was an oceanic tectonic plate under the northern Pacific Ocean south of the Near Islands segment of the Aleutian Islands. It has been subducted under the North American Plate at the Aleutian Trench, being replaced by the Pacific Plate.

<span class="mw-page-title-main">Izu–Bonin–Mariana Arc</span> Convergent boundary in Micronesia

The Izu–Bonin–Mariana (IBM) arc system is a tectonic plate convergent boundary in Micronesia. The IBM arc system extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, the Bonin Islands, and the Mariana Islands; much more of the IBM arc system is submerged below sealevel. The IBM arc system lies along the eastern margin of the Philippine Sea Plate in the Western Pacific Ocean. It is the site of the deepest gash in Earth's solid surface, the Challenger Deep in the Mariana Trench.

<span class="mw-page-title-main">Accretionary wedge</span> The sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary

An accretionary wedge or accretionary prism forms from sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the downgoing slab of oceanic crust, but in some cases the wedge includes the erosional products of volcanic island arcs formed on the overriding plate.

<span class="mw-page-title-main">Molucca Sea Plate</span> Small fully subducted tectonic plate near Indonesia

Located in the western Pacific Ocean near Indonesia, the Molucca Sea Plate has been classified by scientists as a fully subducted microplate that is part of the Molucca Sea Collision Complex. The Molucca Sea Plate represents the only known example of divergent double subduction (DDS), which describes the subduction on both sides of a single oceanic plate.

This is a list of articles related to plate tectonics and tectonic plates.

<span class="mw-page-title-main">Philippine Mobile Belt</span> Tectonic boundary

In the geology of the Philippines, the Philippine Mobile Belt is a complex portion of the tectonic boundary between the Eurasian Plate and the Philippine Sea Plate, comprising most of the country of the Philippines. It includes two subduction zones, the Manila Trench to the west and the Philippine Trench to the east, as well as the Philippine Fault System. Within the Belt, a number of crustal blocks or microplates which have been shorn off the adjoining major plates are undergoing massive deformation.

<span class="mw-page-title-main">Shirshov Ridge</span> Seabed ridge on the eastern border of the Commander Basin below the Kamchatka Peninsula

The Shirshov Ridge is located on the eastern border of the Commander Basin below the Kamchatka Peninsula. It extends directly southward for a distance of 750 km toward the Aleutian arc in the eastern part of the Bering Sea.

<span class="mw-page-title-main">Commander Basin</span> Basin located in the Pacific

The Commander Basin is located between the Shirshov Ridge and the Kamchatka Peninsula. Its southern boundary is the Aleutian arc and occupies the western part of the Bering Sea. The Kamchatka Strait provides a deep water access to the basin from the southwest.

<span class="mw-page-title-main">Bowers Ridge</span> Currently seismically inactive ridge in the southern part of the Aleutian Basin

The Bowers Ridge is located in the southern part of the Aleutian Basin. It extends over 900 km in an arc, starting in the southeast at the Aleutian Arc and terminating to the northwest at the Shirshov Ridge. The Bowers Ridge arc separates the Aleutian Basin from the Bowers Basin, which it encloses. The ridge is not currently seismically active. The northern slope of the ridge is steeper than the southern slope. On the Aleutian side, the ridge is rimmed by a trough filled with a sedimentary sequence 9–10 km thick.

The Antarctic Peninsula, roughly 1,000 kilometres (650 mi) south of South America, is the northernmost portion of the continent of Antarctica. Like the associated Andes, the Antarctic Peninsula is an excellent example of ocean-continent collision resulting in subduction. The peninsula has experienced continuous subduction for over 200 million years, but changes in continental configurations during the amalgamation and breakup of continents have changed the orientation of the peninsula itself, as well as the underlying volcanic rocks associated with the subduction zone.

<span class="mw-page-title-main">Geology of the Pacific Ocean</span> Overview about the geology of the Pacific Ocean

The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific Plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth.

The West Philippine Basin, is the oceanic crust located underneath the western part of the Philippine Sea. It was formed during the early Oligocene epoch. To its southwest is the Philippine Trench, and to its east is the Kyushu–Palau Ridge. The West Philippine Basin is deeper and older than the eastern basins and has crustal heat-flow values approaching that of old oceanic crust. It is roughly bisected by the Central Basin Fault zone which comprises a band of high relief running from the northwest corner to the Kyushu–Palau Ridge near 14°N. Characterized by the presence of several submarine plateaus.

<span class="mw-page-title-main">Aleutian subduction zone</span> Convergence boundary between the North American Plate and the Pacific Plate

The Aleutian subduction zone is a 2,500 mi (4,000 km) long convergent boundary between the North American Plate and the Pacific Plate, that extends from the Alaska Range to the Kamchatka Peninsula. Here, the Pacific Plate is being subducted underneath the North American Plate and the rate of subduction changes from west to east from 7.5 to 5.1 cm per year. The Aleutian subduction zone includes two prominent features, the Aleutian Arc and the Aleutian Trench. The Aleutian Arc was created via volcanic eruptions from dehydration of the subducting slab at ~100 km depth. The Aleutian Trench is a narrow and deep morphology that occurs between the two converging plates as the subducting slab dives beneath the overriding plate.

The geology of Costa Rica is part of the Panama Microplate, which is slowly moving north relative to the stable Caribbean Plate.

References

  1. 1 2 New Views of the U.S. Continental Margins (University of New Hampshire)
  2. 1 2 Verzhbitsky, E. V.; M. V. Kononov; V. D. Kotelkin (5 February 2007). "Plate Tectonics of the Northern Part of the Pacific Ocean". Oceanology (In Translation from Okeanologiya ). 47 (5): 705–717. Bibcode:2007Ocgy...47..705V. doi:10.1134/S000143700705013X.

57°N177°E / 57°N 177°E / 57; 177