{"id":1648,"date":"2015-04-29T11:18:57","date_gmt":"2015-04-29T11:18:57","guid":{"rendered":"http:\/\/www.bluehabitats.org\/?page_id=1648"},"modified":"2015-04-29T13:25:20","modified_gmt":"2015-04-29T13:25:20","slug":"abyssal-hills","status":"publish","type":"page","link":"https:\/\/bluehabitats.org\/?page_id=1648","title":{"rendered":"Abyssal hills"},"content":{"rendered":"
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Abyssal hills<\/em> \u2013 Abyssal hills are defined by the IHO (2008) as \u201cAn isolated (or tract of) small elevation(s) on the deep seafloor\u201d.\u00a0 Hills on the seabed at abyssal depths having peaks that rise >300 to <1,000 m above the seafloor were mapped by Harris et al. (2014) as abyssal hills; they are abundant in the region between the mid-ocean ridge and the comparatively flat abyssal plains.\u00a0 These hills have their origins as prominent peaks of the mid-ocean ridge, but subsidence coupled with thick blankets of sediment obscures their original relief.\u00a0 They are the summits of larger features comprised of basaltic ocean crust that pierce through the layers of sediment that rain down from the water column to blanket the seafloor, forming thick deposits that drape over the topography.<\/p>\n

Sediment deposits are generally thinnest near the mid-ocean ridge, because, for one reason, the ocean crust here is youngest and sediments have had less time to accumulate.\u00a0 With increasing distance from the centre of seafloor spreading, the ocean crust is older and the overlying sediment blanket is thicker. Sediment thickness increases (and abyssal hills appear to grow smaller in height) with increasing distance from mid-ocean ridges, in direct proportion to the amount of time that has elapsed since that particular piece of seafloor was created and moved laterally away from the spreading centre, cooled and subsided.\u00a0 The oldest sediment occurs at the far western edge of the Pacific and is around 200 million years old (middle Jurassic).<\/p>\n

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Abyssal classification categories (after Harris et al., 2014).\u00a0 The percentage areas first line refers to percentage of ocean basin area and the second line (in brackets) refers to percentage of abyssal area.<\/em><\/p>\n\n\t\t<\/div>\n\t<\/div>\n

[vc_table vc_table_theme=”classic_blue” allow_html=””]Ocean,Abyssal%20Plain%20Area%20km2,Abyssal%20Plain%20Area%25,Abyssal%20Hills%20Area%20km2,Abyssal%20Hills%20Area%20%25,Abyssal%20Mountains%20Area%20km2,Abyssal%20Mtns.%20Area%20%25%0A|Arctic%20Ocean%0AAbyssal,2%2C068%2C570,15.9%0A(38.7),2%2C244%2C920,17.3%0A(42),1%2C036%2C060,7.98%0A(19.4)|Indian%20Ocean%20%0AAbyssal,21%2C772%2C790,30.5%0A(34.7),30%2C179%2C170,42.3%0A(48),10%2C859%2C500,15.2%0A(17.3)|Mediterranean%20and%20Black%20Sea%20%20-%20Abyssal,612%2C870,20.3%0A(43.6),613%2C830,20.3%0A(43.7),179%2C220,5.93%0A(12.7)|North%20Atlantic%20Ocean%20Abyssal,10%2C255%2C540,22.9%0A(30.4),16%2C477%2C470,36.8%0A(48.9),6%2C987%2C830,15.6%0A(20.8)|North%20Pacific%20Ocean%20Abyssal,24%2C906%2C630,30.4%0A(36.2),29%2C676%2C230,36.2%0A(43.2),14%2C137%2C990,17.3%0A(20.6)|South%20Atlantic%20Ocean%20Abyssal,10%2C033%2C650,24.8%0A(27.4),19%2C511%2C510,48.3%0A(53.3),7%2C031%2C560,17.4%0A(19.2)|South%20Pacific%20Ocean%20Abyssal,22%2C648%2C400,26%0A(28),44%2C059%2C800,50.6%0A(54.4),14%2C299%2C470,16.4%0A(17.7)|Southern%20Ocean%20Abyssal,8%2C565%2C270,42.1%0A(50.4),6%2C688%2C370,32.9%0A(39.3),1%2C749%2C840,8.6%0A(10.3)|All%20Oceans%0AAll%20Abyssal,100%2C863%2C730,27.9%0A(32.9),149%2C451%2C310,41.3%0A(48.7),56%2C281%2C460,15.6%0A(18.4)[\/vc_table]<\/div><\/div><\/div><\/div>\n\t
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References<\/h5>\n

Harris, P.T., MacMillan-Lawler, M., Rupp, J., Baker, E.K., 2014. Geomorphology of the oceans. Marine Geology 352, 4-24.<\/p>\n

IHO, 2008. Standardization of Undersea Feature Names: Guidelines Proposal form Terminology, 4th ed. International Hydrographic Organisation and Intergovernmental Oceanographic Commission, Monaco, p. 32. http:\/\/www.iho.int\/iho_pubs\/bathy\/B-6_e4_EF_Nov08.pdf<\/a><\/p>\n\n\t\t<\/div>\n\t<\/div>\n<\/div><\/div><\/div><\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

Abyssal hills \u2013 Abyssal hills are defined by the IHO (2008) as \u201cAn isolated (or tract of) small elevation(s) on the deep seafloor\u201d.\u00a0 Hills on the seabed at abyssal depths having peaks that rise >300 to <1,000 m above the seafloor were mapped by Harris et al. (2014) as abyssal hills; they are abundant in…<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":1646,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-1648","page","type-page","status-publish","hentry","description-off"],"acf":[],"_links":{"self":[{"href":"https:\/\/bluehabitats.org\/index.php?rest_route=\/wp\/v2\/pages\/1648","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bluehabitats.org\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/bluehabitats.org\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/bluehabitats.org\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/bluehabitats.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1648"}],"version-history":[{"count":7,"href":"https:\/\/bluehabitats.org\/index.php?rest_route=\/wp\/v2\/pages\/1648\/revisions"}],"predecessor-version":[{"id":1719,"href":"https:\/\/bluehabitats.org\/index.php?rest_route=\/wp\/v2\/pages\/1648\/revisions\/1719"}],"up":[{"embeddable":true,"href":"https:\/\/bluehabitats.org\/index.php?rest_route=\/wp\/v2\/pages\/1646"}],"wp:attachment":[{"href":"https:\/\/bluehabitats.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1648"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}