Английская Википедия:Echo Bank

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Echo Bank (also known as Endeavour Bank) is an underwater mountain, part of the Canary Islands Seamount Province and located southwest of the Canary Islands. Of uncertain geologic origin, it is part of a larger cluster of submarine mountains and rises to a depth of Шаблон:Convert below sea level. It has a flat top, indicating that it formerly might have emerged from the sea.

Name

The etymology of "Echo Bank" is unknownШаблон:Sfn but it is also known as Endeavour BankШаблон:Sfn and the name "Echo Bank" might refer to a submarine feature discovered in 1925-1927 and so named after its reflective crest. "Echo Bank" is also the name of an unconfirmed seamount south of the Sargasso Sea.

Geography and geomorphology

Regional

Файл:Morphometry of Concepcion Bank. Evidence of Geological and Biological Processes on a Large Volcanic Seamount of the Canary Islands Seamount Province. 2016 Rivera et al. Fig. 1.PNG

Map of the CISP (Rivera et al., 2016)

Echo Bank is part of the Canary Islands Seamount Province (CISP), which reaches from north of Lanzarote in the Canary Islands to southwest of the archipelago. This province aside from Echo Bank includes Tropic Seamount, The Paps Seamount, Ico Seamount and Drago Seamount but also Essaouira Seamount north of Lanzarote. Especially the southern among these underwater mountains are poorly studied;Шаблон:Sfn together with the Canary Islands proper they form an important volcanic province in the Atlantic Ocean.Шаблон:Sfn Aside from the seamounts, submarine canyons and large debris flows occur in the regionШаблон:Sfn such as the Sahara Slide which has run around Echo Bank.Шаблон:Sfn

Local

Echo Bank rises from the continental slope to a depth of about Шаблон:Convert below sea level, making it the shallowest seamount in the region.Шаблон:Sfn It has a almost circularШаблон:Sfn maximally Шаблон:Convert wide flat top like a guyot at a depth of Шаблон:Convert. There are small depressions on the topi. Volcanic cones which reach depths of Шаблон:ConvertШаблон:Sfn cluster in the central summit platform.Шаблон:Sfn Around the summit lie terraces and scarps, with the terraces particularly pronounced on the eastern sideШаблон:Sfn while the western side has only two.Шаблон:Sfn This may reflect a slight tilt of the seamount.Шаблон:Sfn The slopes of the seamount are steep and cut by curved slide scars and gullies which both reach lengths of Шаблон:Convert. Echo Bank is Шаблон:Convert wide with a round shape and a Шаблон:Convert long ridge to the northwest and rests on a seafloor with a minimum depth of Шаблон:Convert.Шаблон:Sfn

Northwest of Echo Bank lies first at Шаблон:Convert distanceШаблон:Sfn The Paps Seamount and after a group of submarine hills comes Ico Seamount, while southwest lies Drago Seamount and south-southwest lies Tropic SeamountШаблон:Sfn Шаблон:Convert away.Шаблон:Sfn The San Borondón ridge connects the two seamounts.Шаблон:Sfn Northeast from Echo Bank lies first Hierro Seamount and then the island of El Hierro.Шаблон:Sfn

Geology

The geological origin of the Canary Islands Seamounts are unclear, with various hotspot processes as well as crustal and mantle phenomena proposed.Шаблон:Sfn Volcanic activity at Echo and Tropic seamounts was probably focused and generated a circular volcanic structure, while at Drago and The Paps it was controlled by lineaments and thus formed elongated edifices.Шаблон:Sfn

Composition

Dredging at Echo Bank has yielded basaltic lapillistones, carbonates, coral debris, intermediate volcanic rocks, limestone of hemipelagic origin, manganese crusts, sandstone of volcanic and calcarenite origin and vesicular basalt.Шаблон:Sfn The volcanic rocks at the Canary Islands seamounts like those of the Canary Islands are classified as alkalic;Шаблон:Sfn the basaltic rocks contain clinopyroxene while the rare intermediary volcanic rocks contain amphibole.Шаблон:Sfn

Dredged samples of the ferromanganese crusts consist mainly of goethite and manganese dioxide and minor amounts of calcite, phyllosilicate and quartz.Шаблон:Sfn The ferromanganese deposits which occur on the Canary Islands Seamounts including at Echo Bank reach thicknesses of Шаблон:Convert and are rich in cobalt and other elements of industrial significance; thus such submarine deposits have been considered to be targets for future mining efforts.Шаблон:Sfn

Environment

A number of separate water masses surround Echo Bank, which originate from regions such as the North Atlantic, the South Atlantic and Antarctica and are stacked over each other.Шаблон:Sfn In general, the region is under the influence of the nutrient-poor waters of the subtropical gyre and the upwelling regions off northwestern Africa.Шаблон:Sfn

Bottom net trawlings of Echo Bank have revealed remarkable findingsШаблон:Sfn such as a rich decapod fauna.Шаблон:Sfn African cuttlefish,Шаблон:Sfn the barnacle Poecilasma aurantia, the common cuttlefish,Шаблон:Sfn the elegant cuttlefishШаблон:Sfn and the giant African cuttlefish occur at Echo Bank; the giant African cuttlefish is the most commercially important cuttlefish in the region.Шаблон:Sfn In addition, the bobtail squids Rossia and SepiolaШаблон:Sfn and the ram's horn squid have been found at Echo Bank.Шаблон:Sfn Shoals of fish were frequently observed on the seamount. In 1960–1970, snapper fisheries at Echo Bank were replaced by cephalopod fisheries.Шаблон:Sfn

Geologic history

An age of 72 million years has been established for Echo Bank.Шаблон:Sfn The flat top of Echo Bank has been interpreted as having formed during subaerial erosion, implying that the seamount was once an island although the evidence for such is less clear than at Tropic SeamountШаблон:Sfn and alternative explanations for the flat summit exist.Шаблон:Sfn Echo Bank is currently undergoing sedimentation and it appears to be volcanically inactive.Шаблон:Sfn There is evidence of recent landsliding, however,Шаблон:Sfn and cone-shaped topographic anomalies could indicate recent volcanism.Шаблон:Sfn One of these landslides may have occurred between 339,000 and 869,000 years ago.Шаблон:Sfn

References

Sources

• Шаблон:Cite journal
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• Шаблон:Cite web
• Шаблон:Cite journal
• Шаблон:Cite journal
• Шаблон:Cite journal
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• Шаблон:Cite conference