Map showing the location of oceanic plateaus (in green) in the Australia-New Zealand region of the South Pacific
An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides.[1]
There are 184 oceanic plateaus in the world, covering an area of 18,486,600 km2 (7,137,700 sq mi) or about 5.11% of the oceans.[2] The South Pacific region around Australia and New Zealand contains the greatest number of oceanic plateaus (see map).
In contrast to continental flood basalts, most igneous oceanic plateaus erupt through young and thin (6–7 km (3.7–4.3 mi)) mafic or ultra-mafic crust and are therefore uncontaminated by felsic crust and representative for their mantle sources. These plateaus often rise 2–3 km (1.2–1.9 mi) above the surrounding ocean floor and are more buoyant than oceanic crust. They therefore tend to withstand subduction, more-so when thick and when reaching subduction zones shortly after their formations. As a consequence, they tend to "dock" to continental margins and be preserved as accretedterranes. Such terranes are often better preserved than the exposed parts of continental flood basalts and are therefore a better record of large-scale volcanic eruptions throughout Earth's history. This "docking" also means that oceanic plateaus are important contributors to the growth of continental crust. Their formations often had a dramatic impact on global climate, such as the most recent plateaus formed, the three, large, Cretaceous oceanic plateaus in the Pacific and Indian Ocean: Ontong Java, Kerguelen, and Caribbean.[4]
Geologists believe that igneous oceanic plateaus may well represent a stage in the development of continental crust as they are generally less dense than oceanic crust while still being denser than normal continental crust.
Density differences in crustal material largely arise from different ratios of various elements, especially silicon. Continental crust has the highest amount of silicon (such rock is called felsic). Oceanic crust has a smaller amount of silicon (mafic rock). Igneous oceanic plateaus have a ratio intermediate between continental and oceanic crust, although they are more mafic than felsic.
However, when a plate carrying oceanic crust subducts under a plate carrying an igneous oceanic plateau, the volcanism which erupts on the plateau as the oceanic crust heats up on its descent into the mantle erupts material which is more felsic than the material which makes up the plateau. This represents a step toward creating crust which is increasingly continental in character, being less dense and more buoyant. If an igneous oceanic plateau is subducted underneath another one, or under existing continental crust, the eruptions produced thereby produce material that is yet more felsic, and so on through geologic time.
^Hildenbrand, Anthony; Weis, Dominique; Madureira, Pedro; Margues, Fernando Ornelas (2014). "Recent plate re-organization at the Azores Triple Junction: Evidence from combined geochemical and geochronological data on Faial, S. Jorge and Terceira volcanic islands". Lithos. 210: 27. Bibcode:2014Litho.210...27H. doi:10.1016/j.lithos.2014.09.009. hdl:10174/13522. ISSN 0024-4937.
^Lee, E.Y.; Wolfgring, Erik; Tejada, M.L.G.; et al. (2020). "Early Cretaceous subsidence of the Naturaliste Plateau defined by a new record of volcaniclastic-rich sequence at IODP Site U1513" (PDF). Gondwana Research. 82: 1-11. Bibcode:2020GondR..82....1L. doi:10.1016/j.gr.2019.12.007. hdl:2434/707329. S2CID 213041290.
Sourcesedit
Boldreel, L. O.; Andersen, M. S. (1994). "Tertiary development of the Faeroe-Rockall Plateau based on reflection seismic data". Bulletin of the Geological Society of Denmark. 41 (2): 162–180. doi:10.37570/bgsd-1995-41-15. Retrieved 1 May 2017.
Harris, P. T.; Macmillan-Lawler, M.; Rupp, J.; Baker, E. K. (2014). "Geomorphology of the oceans". Marine Geology. 352: 4–24. Bibcode:2014MGeol.352....4H. doi:10.1016/j.margeo.2014.01.011. Retrieved 30 April 2017.
IHO (September 2013). Standardization of Undersea Feature Names B-6 (PDF) (Report) (4.1.0 ed.). Monaco: International Hydrographic Organization. Retrieved 30 April 2017. (updated February 2017)
Kerr, A. C. (2013). "Oceanic plateau". In Holland, H. D.; Turekian, K. K. (eds.). Treatise on Geochemistry (2nd ed.). Amsterdam; San Diego, CA, USA: Elsevier. pp. 631–667. doi:10.1016/B978-0-08-095975-7.00320-X. ISBN9780080983004. OCLC 864682251. Retrieved 30 April 2017.
Mooney, W. D.; Laske, G.; Masters, T. G. (1998). "CRUST 5.1: A global crustal model at 5°×5°". Journal of Geophysical Research: Solid Earth. 103 (B1): 727–747. Bibcode:1998JGR...103..727M. doi:10.1029/97JB02122. Retrieved 30 April 2017.
Uenzelmann-Neben, G.; Gohl, K.; Ehrhardt, A.; Seargent, M. (1999). "Agulhas Plateau, SW Indian Ocean: New Evidence for Excessive Volcanism" (PDF). Geophysical Research Letters. 26 (13): 1941–1944. Bibcode:1999GeoRL..26.1941U. doi:10.1029/1999gl900391. S2CID 129742780.
External linksedit
Gsa.confex.com: "Oceanic Plateaus: Nuclei for Archean Cratons" 2012-02-06 at the Wayback Machine
Tristan.ferroir.free.fr: "On the oceanic plateaux"—(in French)
November 29, 2023
oceanic, plateau, confused, with, volcanic, plateau, showing, location, oceanic, plateaus, green, australia, zealand, region, south, pacifican, oceanic, submarine, plateau, large, relatively, flat, elevation, that, higher, than, surrounding, relief, with, more. Not to be confused with Volcanic plateau 3 03 S 160 23 E 3 050 S 160 383 E 3 050 160 383 Map showing the location of oceanic plateaus in green in the Australia New Zealand region of the South PacificAn oceanic or submarine plateau is a large relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides 1 There are 184 oceanic plateaus in the world covering an area of 18 486 600 km2 7 137 700 sq mi or about 5 11 of the oceans 2 The South Pacific region around Australia and New Zealand contains the greatest number of oceanic plateaus see map Oceanic plateaus produced by large igneous provinces are often associated with hotspots mantle plumes and volcanic islands such as Iceland Hawaii Cape Verde and Kerguelen The three largest plateaus the Caribbean Ontong Java and Mid Pacific Mountains are located on thermal swells Other oceanic plateaus however are made of rifted continental crust for example the Falkland Plateau Lord Howe Rise and parts of Kerguelen Seychelles and Arctic ridges 3 Plateaus formed by large igneous provinces were formed by the equivalent of continental flood basalts such as the Deccan Traps in India and the Snake River Plain in the United States In contrast to continental flood basalts most igneous oceanic plateaus erupt through young and thin 6 7 km 3 7 4 3 mi mafic or ultra mafic crust and are therefore uncontaminated by felsic crust and representative for their mantle sources These plateaus often rise 2 3 km 1 2 1 9 mi above the surrounding ocean floor and are more buoyant than oceanic crust They therefore tend to withstand subduction more so when thick and when reaching subduction zones shortly after their formations As a consequence they tend to dock to continental margins and be preserved as accreted terranes Such terranes are often better preserved than the exposed parts of continental flood basalts and are therefore a better record of large scale volcanic eruptions throughout Earth s history This docking also means that oceanic plateaus are important contributors to the growth of continental crust Their formations often had a dramatic impact on global climate such as the most recent plateaus formed the three large Cretaceous oceanic plateaus in the Pacific and Indian Ocean Ontong Java Kerguelen and Caribbean 4 Contents 1 Role in crust mantle recycling 2 List of oceanic plateaus 2 1 Continental oceanic plateaus 2 2 Igneous oceanic plateaus 3 See also 4 References 4 1 Notes 4 2 Sources 5 External linksRole in crust mantle recycling editGeologists believe that igneous oceanic plateaus may well represent a stage in the development of continental crust as they are generally less dense than oceanic crust while still being denser than normal continental crust Density differences in crustal material largely arise from different ratios of various elements especially silicon Continental crust has the highest amount of silicon such rock is called felsic Oceanic crust has a smaller amount of silicon mafic rock Igneous oceanic plateaus have a ratio intermediate between continental and oceanic crust although they are more mafic than felsic However when a plate carrying oceanic crust subducts under a plate carrying an igneous oceanic plateau the volcanism which erupts on the plateau as the oceanic crust heats up on its descent into the mantle erupts material which is more felsic than the material which makes up the plateau This represents a step toward creating crust which is increasingly continental in character being less dense and more buoyant If an igneous oceanic plateau is subducted underneath another one or under existing continental crust the eruptions produced thereby produce material that is yet more felsic and so on through geologic time List of oceanic plateaus editGlobal distribution of oceanic plateaus 5 Ocean Area km2 Plateauarea Number ofplateaus Average plateauarea km2 Arctic Ocean 1 193 740 9 19 12 99 480Indian Ocean 5 036 870 7 06 37 136 130North Atlantic Ocean 1 628 360 3 64 36 45 230North Pacific Ocean 1 856 790 2 26 33 56 270South Atlantic Ocean 1 220 230 3 02 9 135 580South Pacific Ocean 7 054 800 8 09 50 141 100Southern Ocean 495 830 2 44 12 41 320World Ocean 18 486 610 5 11 184 100 470 nbsp The Rockall Plateau in the North Atlantic is underlain by continental crust It rifted from Greenland during the opening of the North Atlantic 6 Continental oceanic plateaus edit Campbell Plateau South Pacific Challenger Plateau South Pacific Exmouth Plateau Indian Falkland Plateau South Atlantic Lord Howe Rise South Pacific Rockall Plateau 6 North Atlantic Igneous oceanic plateaus edit Agulhas Plateau 7 Southwest Indian Azores Plateau North Atlantic 8 Broken Plateau Indian Caribbean Colombian Plateau Caribbean Exmouth Plateau Indian Hikurangi Plateau Southwest Pacific Iceland Plateau North Atlantic Kerguelen Plateau Indian Magellan Rise Pacific Manihiki Plateau Southwest Pacific Mascarene Plateau Indian Naturaliste Plateau Indian 9 Ontong Java Plateau Southwest Pacific Shatsky Rise North Pacific Voring Plateau North Atlantic Wrangellia Terrane Northeast Pacific Yermak Plateau Arctic See also edit nbsp Oceans portalAbyssal plain Bathymetry Glossary of landforms Ocean bankReferences editNotes edit IHO 2013 pp 2 12 Harris et al 2014 Plateaus Supplementary Table 20 p 16 Mooney Laske amp Masters 1998 Anomalous Crust Oceanic Plateaus Hotspots and Rifts pp 754 755 Kerr 2013 p 632 Harris et al 2014 Supplementary table 20 a b Boldreel amp Andersen 1994 p 163 Uenzelmann Neben Gohl amp Ehrhardt 1999harvnb error no target CITEREFUenzelmann NebenGohlEhrhardt1999 help Hildenbrand Anthony Weis Dominique Madureira Pedro Margues Fernando Ornelas 2014 Recent plate re organization at the Azores Triple Junction Evidence from combined geochemical and geochronological data on Faial S Jorge and Terceira volcanic islands Lithos 210 27 Bibcode 2014Litho 210 27H doi 10 1016 j lithos 2014 09 009 hdl 10174 13522 ISSN 0024 4937 Lee E Y Wolfgring Erik Tejada M L G et al 2020 Early Cretaceous subsidence of the Naturaliste Plateau defined by a new record of volcaniclastic rich sequence at IODP Site U1513 PDF Gondwana Research 82 1 11 Bibcode 2020GondR 82 1L doi 10 1016 j gr 2019 12 007 hdl 2434 707329 S2CID 213041290 Sources edit Boldreel L O Andersen M S 1994 Tertiary development of the Faeroe Rockall Plateau based on reflection seismic data Bulletin of the Geological Society of Denmark 41 2 162 180 doi 10 37570 bgsd 1995 41 15 Retrieved 1 May 2017 Harris P T Macmillan Lawler M Rupp J Baker E K 2014 Geomorphology of the oceans Marine Geology 352 4 24 Bibcode 2014MGeol 352 4H doi 10 1016 j margeo 2014 01 011 Retrieved 30 April 2017 IHO September 2013 Standardization of Undersea Feature Names B 6 PDF Report 4 1 0 ed Monaco International Hydrographic Organization Retrieved 30 April 2017 updated February 2017 Kerr A C 2013 Oceanic plateau In Holland H D Turekian K K eds Treatise on Geochemistry 2nd ed Amsterdam San Diego CA USA Elsevier pp 631 667 doi 10 1016 B978 0 08 095975 7 00320 X ISBN 9780080983004 OCLC 864682251 Retrieved 30 April 2017 Mooney W D Laske G Masters T G 1998 CRUST 5 1 A global crustal model at 5 5 Journal of Geophysical Research Solid Earth 103 B1 727 747 Bibcode 1998JGR 103 727M doi 10 1029 97JB02122 Retrieved 30 April 2017 Uenzelmann Neben G Gohl K Ehrhardt A Seargent M 1999 Agulhas Plateau SW Indian Ocean New Evidence for Excessive Volcanism PDF Geophysical Research Letters 26 13 1941 1944 Bibcode 1999GeoRL 26 1941U doi 10 1029 1999gl900391 S2CID 129742780 External links editGsa confex com Oceanic Plateaus Nuclei for Archean Cratons Archived 2012 02 06 at the Wayback Machine Tristan ferroir free fr On the oceanic plateaux in French Retrieved from https en wikipedia org w index php title Oceanic plateau amp oldid 1171004670, wikipedia, wiki, book, books, library,
