Anton Dohrn Seamount: Difference between revisions
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== Geology == |
== Geology == |
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The [[crust]] underneath Anton Dohrn Seamount is much thinner than underneath the [[British Isles]] and the [[Rockall Plateau]] east and west of the seamount, respectively, and the [[ |
The [[crust]] underneath Anton Dohrn Seamount is much thinner than underneath the [[British Isles]] and the [[Rockall Plateau]] east and west of the seamount, respectively, and the [[Mohorovičić discontinuity]] is located at a shallower depth.{{sfn|Jones|Siddall|Thirlwall|Chroston|1994|p=238}} It may be either stretched [[continental crust]] or [[oceanic crust]], and is covered by sediments.{{sfn|Jones|Siddall|Thirlwall|Chroston|1994|p=239}} At Anton Dohrn Seamount it appears to be unusually shallow, perhaps due to the [[Iceland plume]]'s buoyancy. The Iceland plume has uplifted terrain as far as {{convert|1000|km}} from the plume.{{sfn|Jones|Siddall|Thirlwall|Chroston|1994|p=245}} |
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[[Basalt]]ic rocks, including [[breccia]], have been dredged from the seamount. The rocks contain [[feldspar]] and [[olivine]] [[phenocryst]]s as well as [[plagioclase]]. They are covered with [[ferromanganese]] crusts{{sfn|Jones|Siddall|Thirlwall|Chroston|1994|p=240}} and vesicles contain [[carbonate]]s, [[clay]] and [[ |
[[Basalt]]ic rocks, including [[breccia]], have been dredged from the seamount. The rocks contain [[feldspar]] and [[olivine]] [[phenocryst]]s as well as [[plagioclase]]. They are covered with [[ferromanganese]] crusts{{sfn|Jones|Siddall|Thirlwall|Chroston|1994|p=240}} and vesicles contain [[carbonate]]s, [[clay]] and [[Zeolite|zeolites]] which formed through alteration.{{sfn|Jones|Siddall|Thirlwall|Chroston|1994|p=241}} [[Chalk]]s of [[Maastricht]]ian age have also been recovered.{{sfn|Jones|Siddall|Thirlwall|Chroston|1994|p=240}} |
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== Geologic history == |
== Geologic history == |
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Revision as of 10:29, 22 February 2020
| Anton Dohrn Seamount | |
|---|---|
 | |
  Anton Dohrn Seamount (North Atlantic) | |
| Summit depth | 600 metres |
| Height | 1,500 m |
| Location | |
| Location | North Atlantic Ocean |
| Coordinates | 57°30′N 11°00′W / 57.500°N 11.000°W |
| Country | United Kingdom (EEZ) |
| Geology | |
| Type | Guyot |
| Last eruption | ~40 million years |
The Anton Dohrn Seamount is a guyot in the Rockall Trough in the northeast Atlantic. It was named after the German fishery research vessel which discovered it at the end of the 1950s which, in turn, had been named after the 19th-century biologist Anton Dohrn.
The feature rises from approximately 2,100 metres to 600 metres below sea level and has a sedimentary layer approximately 100 metres thick. It arose through episodic volcanic activity between 70 and 40 million years ago.[2][3]
Around the base of the seamount is a slight "moat" where the sea-bottom is at a lower depth than the surrounding terrain.
Releasing their findings in August 2016, the Deep Links project team, a collaboration between Plymouth University, the University of Oxford, the Joint Nature Conservation Committee and the British Geological Survey, spent six weeks at sea on board the RSS James Cook deploying robot submersibles to film, photograph and collect samples from an exceptionally diverse coral reef environment now revealed on the top of the plateau-like seamount.
Geography and geomorphology
Anton Dohrn Seamount is located approximately halfway between St Kilda (Hebrides) and Rockall. It lies in the Rockall Trough, an over 2,000 metres (6,600 ft) submarine depression of unclear origin. North-northeast lies the Rosemary Bank and Hebrides Terrace Seamount is found south-southeast from the seamount.[4]
Anton Dohrn Seamount is a guyot[4] with a flat top at 1 kilometre (0.62 mi) depth. The shallowest point of the seamount lies at less than 600 metres (2,000 ft) depth.[1] A 100 metres (330 ft) thick layer of sediment covers the flat top.[5] Its steep slopes do not appear to be covered with sediments.[1]
Geology
The crust underneath Anton Dohrn Seamount is much thinner than underneath the British Isles and the Rockall Plateau east and west of the seamount, respectively, and the Mohorovičić discontinuity is located at a shallower depth.[4] It may be either stretched continental crust or oceanic crust, and is covered by sediments.[1] At Anton Dohrn Seamount it appears to be unusually shallow, perhaps due to the Iceland plume's buoyancy. The Iceland plume has uplifted terrain as far as 1,000 kilometres (620 mi) from the plume.[6]
Basaltic rocks, including breccia, have been dredged from the seamount. The rocks contain feldspar and olivine phenocrysts as well as plagioclase. They are covered with ferromanganese crusts[7] and vesicles contain carbonates, clay and zeolites which formed through alteration.[8] Chalks of Maastrichtian age have also been recovered.[7]
Geologic history
During the Cretaceous the seamount was about 2 kilometres (1.2 mi) higher than present; presumably it was then eroded during the Paleocene when a wave of erosion took place in western Britain and stripped much of the volcanic centres of northwest Scotland.[6]
Ecology
The coral Lophelia prolifera grows on Anton Dohrn Seamount.[7]
References
- ^ a b c d Jones et al. 1994, p. 239.
- ^ O'Connor, Stofferes, Wijbrans, Shannon and Morrissey (2000). Evidence from episodic seamount volcanism for pulsing of the Iceland plume in the past 70 Myr Archived April 11, 2007, at the Wayback Machine, Nature 408, 954–958.
- ^ "New discovery of deep-water coral reefs in UK waters". British Geological Survey. 2010. Retrieved October 20, 2019.
- ^ a b c Jones et al. 1994, p. 238.
- ^ Jones et al. 1994, p. 244.
- ^ a b Jones et al. 1994, p. 245.
- ^ a b c Jones et al. 1994, p. 240.
- ^ Jones et al. 1994, p. 241.
Sources
- Jones, Ejw; Siddall, R.; Thirlwall, Mf; Chroston, Pn; Lloyd, Aj (1994-01-01). "Seamount,anton,dohrn and the evolution of the rockall trough". Oceanologica Acta. 17 (3): 237–247. ISSN 0399-1784.
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External links
- Anton Dohrn Seamount MPA
- WWF report on seamounts of the Northeast Atlantic (PDF)
- BBC webpage report on the 2016 report on coral reef habitat
- Anton Dohrn — Fisheries Research Vessel
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