Continent

2017-08-23T01:57:49Z

Miguel4g123: se quitaron los continente north america y south america y se cambiaron por america simplemente

{{Other uses}}
{{Use dmy dates|date=April 2011}}
[[File:Continental models-Australia.gif|thumb|300px|Animated, colour-coded map showing the various continents and regions. [[Boundaries between the continents of Earth|Depending on the convention and model]], some continents may be consolidated or subdivided: for example, [[Eurasia]] is most often subdivided into [[Asia]] and [[Europe]] (red shades), while [[North America|North]] and [[South America]] are sometimes recognised as [[Americas|one American continent]] (green shades).]]

A '''continent''' is one of several very large [[Land#Land mass|landmasses]] on [[Earth]]. Generally identified by [[convention (norm)|convention]] rather than any strict criteria, up to seven regions are commonly regarded as continents. Ordered from largest in size to smallest, they are: [[Asia]], [[Africa]], [[Americas|America]] [[Antarctica]], [[Europe]], and [[Australia (continent)|Australia]].<ref name="NatlGeo1">{{cite web|url=http://travel.nationalgeographic.com/places/continents/|title=Continents: What is a Continent?|publisher=[[National Geographic (magazine)|National Geographic]]|archivedate=2009-06-29|archiveurl=https://web.archive.org/web/20090629180448/http://travel.nationalgeographic.com/places/continents/}} "Most people recognize seven continents—Asia, Africa, North America, South America, Antarctica, Europe, and Australia, from largest to smallest—although sometimes Asia and Europe are considered a single continent, Eurasia."</ref>

[[Geology|Geologically]] the continents largely correspond to areas of [[continental crust]] that are found on the [[continental plate]]s. However some areas of continental crust are [[submerged continent|regions covered with water]] not usually included in the list of continents. The area referred to as [[Zealandia]] is one such area (see [[Continent#Submerged continents|submerged continents]] below).

Islands are frequently grouped with a neighbouring continent to divide all the world's land into geopolitical regions. Under this scheme, most of the island countries and territories in the [[Pacific Ocean]] are grouped together with the [[Australia (continent)|continent of Australia]] to form a geopolitical region called ''[[Oceania]]''.

== Definitions and application ==
[[File:Dymaxion map unfolded-no-ocean.png|thumb|right|A [[Dymaxion map]] shows land masses with minimal shape distortion.]]

By convention, "continents are understood to be large, continuous, discrete masses of land, ideally separated by expanses of water."{{sfnp|Lewis & Wigen, The Myth of Continents|1997|p=21}} Several of the seven conventionally recognized continents are not discrete landmasses separated completely by water. The criterion "large" leads to arbitrary classification: [[Greenland]], with a surface area of {{convert|2166086|sqkm}} is considered the world's largest island, while Australia, at {{convert|7617930|sqkm}} is deemed the smallest continent.

[[Earth]]'s major landmasses all have coasts on a single, continuous [[World Ocean]], which is divided into a number of principal [[ocean]]ic components by the continents and various geographic criteria.<ref>"[http://www.answers.com/Ocean#Encyclopedia Ocean]". ''[[Columbia Encyclopedia]]'' (2006). New York: [[Columbia University Press]]. Retrieved 20 February 2007.</ref><ref name="UNAoO">"[http://www.oceansatlas.com/unatlas/about/physicalandchemicalproperties/background/seemore1.html Distribution of land and water on the planet] {{webarchive |url=https://web.archive.org/web/20080531103749/http://www.oceansatlas.com/unatlas/about/physicalandchemicalproperties/background/seemore1.html |date=31 May 2008 }}." ''[http://www.oceansatlas.com/ UN Atlas of the Oceans] {{webarchive |url=https://web.archive.org/web/20080915105349/http://www.oceansatlas.com/ |date=15 September 2008 }}'' (2004). Retrieved 20 February 2007.</ref>

=== Extent ===
The most restricted meaning of ''continent'' is that of a continuous<ref>"continent n. 5. a." (1989) ''[[Oxford English Dictionary]]'', 2nd edition. [[Oxford University Press]] ; "continent1 n." (2006) ''The [[Concise Oxford English Dictionary]]'', 11th edition revised. (Ed.) Catherine Soanes and Angus Stevenson. Oxford University Press; "continent1 n." (2005) ''The [[New Oxford American Dictionary]]'', 2nd edition. (Ed.) [[Erin McKean]]. Oxford University Press; "continent [2, n] 4 a" (1996) ''[[Webster's Dictionary#WebsThird New International|Webster's Third New International Dictionary, Unabridged]]''. [[ProQuest|ProQuest Information and Learning]] ; "continent" (2007) ''[[Encyclopædia Britannica]]''. Retrieved 14 January 2007, from Encyclopædia Britannica Online.</ref> area of land or mainland, with the coastline and any land boundaries forming the edge of the continent. In this sense the term ''[[continental Europe]]'' (sometimes referred to in Britain as "the Continent") is used to refer to mainland Europe, excluding [[island]]s such as [[Great Britain]], [[Ireland]], [[Malta]] and [[Iceland]], and the term ''continent of Australia'' may refer to the [[Australia (continent)|mainland of Australia]], excluding [[Tasmania]] and [[New Guinea]]. Similarly, the ''[[contiguous United States|continental United States]]'' refers to the 48 contiguous states and the [[District of Columbia]] in central North America and may include [[Alaska]] in the northwest of the continent (the two being separated by [[Canada]]), while excluding [[Hawaii]], [[Puerto Rico]], and [[Guam]] in the oceans.

From the perspective of [[geology]] or [[physical geography]], ''continent'' may be extended beyond the confines of continuous dry land to include the shallow, submerged adjacent area (the [[continental shelf]])<ref>"continent [2, n] 6" (1996) ''[[Webster's Dictionary#Webster's Third New International|Webster's Third New International Dictionary, Unabridged]]''. [[ProQuest|ProQuest Information and Learning]]. "a large segment of the earth's outer shell including a [[Terrestrial ecoregion|terrestrial]] continent and the adjacent continental shelf"</ref> and the [[island]]s on the shelf ([[Island#Continental islands|continental islands]]), as they are structurally part of the continent.<ref>{{cite book |last=Monkhouse |first=F. J. |author2=John Small |title=A Dictionary of the Natural Environment |year=1978 |publisher=Edward Arnold |location=London |id= |pages= 67–68 |quote=structurally it includes shallowly submerged adjacent areas (continental shelf) and neighbouring islands }}</ref>

From this perspective the edge of the continental shelf is the true edge of the continent, as shorelines vary with changes in sea level.<ref name=Ollier>[[Cliff Ollier|Ollier, Cliff D.]] (1996). Planet Earth. In Ian Douglas (Ed.), ''Companion Encyclopedia of Geography: The Environment and Humankind''. London: Routledge, p. 30. "Ocean waters extend onto continental [[Rock (geology)|rocks]] at continental shelves, and the true edges of the continents are the steeper continental slopes. The actual shorelines are rather accidental, depending on the height of sea-level on the sloping shelves."</ref> In this sense the islands of Great Britain and Ireland are part of Europe, while Australia and the island of New Guinea together form a continent.

[[File:Island nations.svg|thumb|300px|Map of [[island country|island countries]]: these states are often grouped geographically with a neighboring continental landmass.]]

As a [[social constructionism|cultural construct]], the concept of a continent may go beyond the continental shelf to include [[Island#Oceanic islands|oceanic islands]] and continental fragments. In this way, Iceland is considered part of Europe and [[Madagascar]] part of Africa. Extrapolating the concept to its extreme, some geographers group the [[Australasia]]n continental plate with other islands in the Pacific into one continent called [[Oceania]]. This divides the entire land surface of Earth into continents or quasi-continents.<ref>{{harvp|Lewis & Wigen, The Myth of Continents|1997 |page=40 |ps=: "The joining of Australia with various Pacific islands to form the quasi continent of Oceania ... "}}</ref>

=== Separation ===
{{Main|Boundaries between the continents of Earth}}
{{See also|List of transcontinental countries}}

The ideal criterion that each continent be a discrete landmass is commonly relaxed due to historical conventions. Of the seven most globally recognized continents, only Antarctica and Australia are completely separated from other continents by ocean. Several continents are defined not as absolutely distinct bodies but as "''more or less'' discrete masses of land".{{sfnp|Lewis & Wigen, The Myth of Continents|1997|p=35}} Asia and Africa are joined by the [[Isthmus of Suez]], and North and South America by the [[Isthmus of Panama]]. In both cases, there is no complete separation of these landmasses by water (disregarding the [[Suez Canal]] and [[Panama Canal]], which are both narrow and shallow, as well as being artificial). Both these [[isthmus]]es are very narrow compared to the bulk off the landmasses they unite.

North America and South America are treated as separate continents in the seven-continent model. However, they may also be viewed as a single continent known as America or the [[Americas]]. This viewpoint was common in the United States until World War II, and remains prevalent in some Asian six-continent models.<ref>{{harvp|Lewis & Wigen, The Myth of Continents|1997 |loc=Chapter 1 |ps=: "While it might seem surprising to find North and South America still joined into a single continent in a book published in the United States in 1937, such a notion remained fairly common until World War II. [...] By the 1950s, however, virtually all American geographers had come to insist that the visually distinct landmasses of North and South America deserved separate designations."}}</ref> This remains the more common vision in Latin American countries, Spain, Portugal, France, Italy and Greece, where they are taught as a single continent.

The criterion of a discrete landmass is completely disregarded if the continuous landmass of Eurasia is classified as two separate continents: Europe and Asia. Physiographically, Europe and South Asia are peninsulas of the Eurasian landmass. However, Europe is widely considered a continent with its comparatively large land area of {{convert|10180000|sqkm}}, while South Asia, with less than half that area, is considered a subcontinent. The alternative view—in geology and geography—that Eurasia is a single continent results in a six-continent view of the world. Some view separation of Eurasia into Asia and Europe as a residue of [[Eurocentrism]]: "In physical, cultural and historical diversity, [[China]] and [[India]] are comparable to the entire European landmass, not to a single European country. [...]."{{sfnp|Lewis & Wigen, The Myth of Continents|1997|p=? }} However, for historical and cultural reasons,{{which|date=May 2017}} the view of Europe as a separate continent continues in several categorizations.{{citation needed|date=May 2017}}

If continents are defined strictly as discrete landmasses, embracing all the contiguous land of a body, then Africa, Asia, and Europe form a single continent which may be referred to as [[Afro-Eurasia]]. This produces a four-continent model consisting of Afro-Eurasia, America, Antarctica and Australia.

When sea levels were lower during the [[Pleistocene]] [[ice age]]s, greater areas of continental shelf were exposed as dry land, forming [[land bridge]]s. At those times [[Australia (continent)|Australia–New Guinea]] was a single, continuous continent. Likewise the Americas and Afro-Eurasia were joined by the [[Beringia|Bering land bridge]]. Other islands such as Great Britain were joined to the mainlands of their continents. At that time there were just three discrete continents: Afro-Eurasia-America, Antarctica, and Australia-New Guinea.

=== Number ===
{{Anchor|Number}}
There are several ways of distinguishing the continents:

{| class="wikitable" style="margin:auto; text-align:center;"
|-
! colspan="9" | Models
|-
| style="background:#fff;font-size:85%;" colspan="9"|[[File:Seven continents Australia not Oceania.png|center|300px]]<center>Color-coded map showing the various continents. Similar shades exhibit areas that may be consolidated or subdivided.</center>
|-
|'''Four continents'''<ref>{{cite encyclopedia|title=continents|encyclopedia=Encyclopedia of World Geography|volume=1|url=https://books.google.com/books?id=DJgnebGbAB8C&pg=PA215|editor=R. W. McColl|year=2005|publisher=Facts on File, Inc.|ISBN=9780816072293|page=215|accessdate=2012-06-26|quote=And since Africa and Asia are connected at the Suez Peninsula, Europe, Africa, and Asia are sometimes combined as Afro-Eurasia or Eurafrasia.}}</ref>
|colspan="3" |{{small|{{color strip|#fed52e|#c10000|#f33e01}}}} [[Afro-Eurasia]]
|colspan="2" |{{small|{{color strip|#0c0|green}}}} [[Americas|America]]
|{{small|{{color strip|#0040ff}}}} [[Antarctica]]
|{{small|{{color strip|#c04080}}}} [[Australia (continent)|Australia]]
|-
|'''Six continents'''<ref name="HEL"/>
|{{small|{{color strip|#fed52e}}}} [[Africa]]
|{{small|{{color strip|#f33e01}}}} [[Asia]]
|{{small|{{color strip|#c10000}}}} [[Europe]]
|colspan="2" |{{small|{{color strip|#0c0|green}}}} America
|{{small|{{color strip|#0040ff}}}} Antarctica
|{{small|{{color strip|#c04080}}}} Australia
|-
|'''Six continents''' <ref name=Columbia>"[http://www.bartleby.com/65/co/continent.html Continent] {{webarchive|url=https://web.archive.org/web/20070202190101/http://www.bartleby.com/65/co/continent.html |date=2 February 2007 }}". ''[http://www.bartleby.com/65/ The Columbia Encyclopedia] {{webarchive|url=https://web.archive.org/web/20020205073950/http://www.bartleby.com/65/ |date=5 February 2002 }} ''. 2001. New York: Columbia University Press - Bartleby.</ref><ref name=EB />
|{{small|{{color strip|#fed52e}}}} Africa
|colspan="2" |{{small|{{color strip|#c10000|#f33e01}}}} Eurasia
|{{small|{{color strip|#0c0}}}} [[North America]]
|{{small|{{color strip|green}}}} [[South America]]
|{{small|{{color strip|#0040ff}}}} Antarctica
|{{small|{{color strip|#c04080}}}} Australia/[[Oceania]]
|-
|'''Seven continents''' <ref name=EB>"[http://www.britannica.com/ebc/article-9361501 Continent]". ''[[Encyclopædia Britannica]]''. 2006. Chicago: Encyclopædia Britannica, Inc.</ref><ref name=NatlGeo2>[http://www.nationalgeographic.com/xpeditions/atlas/index.html?Parent=world&Mode=d&SubMode=w World], ''[[National Geographic (magazine)|National Geographic]] - [http://www.nationalgeographic.com/xpeditions/ Xpeditions Atlas].'' 2006. Washington, DC: National Geographic Society.</ref><ref name=AoCA>[http://atlas.gc.ca/site/english/maps/reference/international/world/referencemap_image_view The World - Continents] {{webarchive |url=https://web.archive.org/web/20060221064548/http://atlas.gc.ca/site/english/maps/reference/international/world/referencemap_image_view |date=21 February 2006 }}, [http://atlas.nrcan.gc.ca/site/english/index.html ''Atlas of Canada'']</ref><ref name=Oxford1>''[[Oxford English Dictionary|The New Oxford Dictionary of English]].'' 2001. New York: Oxford University Press.</ref><ref name=Encarta>"[http://encarta.msn.com/encyclopedia_761553387/Continent.html Continent]". ''[[Encarta|MSN Encarta Online Encyclopedia 2006]].''. [https://www.webcitation.org/5kwRKkaEZ?url=http://encarta.msn.com/encyclopedia_761553387/Continent.html Archived] 2009-10-31.</ref><ref name=Oxford2>"Continent". McArthur, Tom, ed. 1992. ''The Oxford Companion to the English Language''. New York: Oxford University Press; p. 260.</ref>
|{{small|{{color strip|#fed52e}}}} Africa
|{{small|{{color strip|#f33e01}}}} Asia
|{{small|{{color strip|#c10000}}}} Europe
|{{small|{{color strip|#0c0}}}} North America
|{{small|{{color strip|green}}}} South America
|{{small|{{color strip|#0040ff}}}} Antarctica
|{{small|{{color strip|#c04080}}}} Australia/Oceania
|}

* The seven-continent model is usually taught in [[China]], [[India]], [[Pakistan]], the [[Philippines]], parts of [[Western Europe]] and most [[list of countries by English-speaking population|English-speaking countries]], including [[Australia]]<ref>{{cite web | url = http://www.australiancurriculum.edu.au/humanitiesandsocialsciences/geography/Curriculum/F-10#cdcode=ACHGK009&level=2 | title = F-10 Curriculum Geograph | publisher = Australian Curriculum, Assessment, and Reporting Authority}}</ref> and the [[United Kingdom]].<ref>{{cite web | url = https://www.gov.uk/government/publications/national-curriculum-in-england-geography-programmes-of-study/national-curriculum-in-england-geography-programmes-of-study | title = National curriculum in England: geography programmes of study | publisher = UK Department for Education}}</ref>
* The six-continent combined-Eurasia model is mostly used in [[Russia]], [[Eastern Europe]], and [[Japan]].
* The six-continent combined-America model is often used in [[France]] and its [[list of French possessions and colonies|former possessions]], [[Italy]], [[Portugal]], [[Spain]], [[Romania]], [[Latin America]],<ref>{{cite web|url=http://lema.rae.es/dpd/?key=norteamerica |title=Real Academia Española |publisher=Lema.rae.es |accessdate=2013-09-30}}</ref> and [[Greece]].<ref name="HEL">[https://web.archive.org/web/20100928055209/http://pi-schools.sch.gr/dimotiko/geografia_st/math/math_21_30.pdf] Older/previous official Greek Paedagogical Institute ''6th grade Geography textbook'' (at the [[Wayback Machine]]), 5+1 continents combined-America model; ''Pankosmios Enyklopaidikos Atlas'', CIL Hellas Publications, {{ISBN|84-407-0470-4}}, page 30, 5+1 combined-America continents model; ''Neos Eikonographemenos Geographikos Atlas'', Siola-Alexiou, 6 continents combined-America model; ''Lexico tes Hellenikes Glossas'', Papyros Publications, {{ISBN|978-960-6715-47-1}}, lemma ''continent'' (''epeiros''), 5 continents model; ''Lexico Triantaphyllide'' online dictionary, Greek Language Center (''Kentro Hellenikes Glossas''), lemma ''continent'' (''[http://www.greek-language.gr/greekLang/modern_greek/tools/lexica/search.html?lq=%CE%AE%CF%80%CE%B5%CE%B9%CF%81%CE%BF%CF%82&dq= epeiros]''), 6 continents combined-America model; ''Lexico tes Neas Hellenikes Glossas'', [[Georgios Babiniotis|G.Babiniotes]], Kentro Lexikologias (Legicology Center) LTD Publications, {{ISBN|960-86190-1-7}}, lemma ''continent'' (''epeiros''), 6 continents combined-America model</ref>
**A five-continent model is obtained from this model by excluding Antarctica as uninhabited. This is used, for example in the [[United Nations]]<ref>{{Cite web|url=http://unstats.un.org/unsd/methods/m49/m49regin.htm|title=United Nations Statistics Division- Standard Country and Area Codes Classifications (M49)|website=unstats.un.org|access-date=2016-11-09}}</ref> and in the [[Olympic Charter]].<ref name="OC">{{cite web|url=http://www.olympic.org/Documents/olympic_charter_en.pdf#page=11|title=Preamble|date=8 December 2014|work=Olympic Charter|publisher=International Olympic Committee|page=10|quote=the five interlaced rings, which represent the union of the five continents|accessdate=7 August 2015}}</ref>

The term ''[[Oceania]]'' refers to a group of [[island country|island countries]] and territories in the [[Pacific Ocean]], together with the [[Australia (continent)|continent of Australia]].<ref name="HEL"/><ref name="AoCA"/> [[Pacific islands]] with ties to other continents (such as [[Japan]], [[Hawaii]] or [[Easter Island]]) are usually grouped with those continents rather than Oceania. This term is used in several different continental models instead of [[Australia (continent)|Australia]].

== Highest and lowest points ==
{{See also|Extremes on Earth|Extreme points of Earth|Seven Summits}}

The following table lists the seven continents with their highest and lowest points on land, sorted in decreasing highest points.

{| class="wikitable sortable"
|-
! Continent !! Highest point !! Elevation (m) !! Elevation (ft) !! Country or territory containing highest point !! Lowest point !! Elevation (m) !! Elevation (ft) !! Country or territory containing lowest point
|-
| Asia || [[Mount Everest]] || {{convert|8848|m|disp=table}} || China and [[Nepal]] || [[Dead Sea]] || {{convert|-427|m|disp=table}} || [[Israel]], [[Jordan]] and [[State of Palestine|Palestine]]
|-
| South America || [[Aconcagua]] || {{convert|6960|m|disp=table}} || [[Argentina]] || [[Laguna del Carbón]] || {{convert|-105|m|disp=table}} || [[Argentina]]
|-
| North America || [[Denali]] || {{convert|6198|m|disp=table}} || United States || [[Death Valley]] † || {{convert|-86|m|disp=table}} || United States
|-
| Africa || [[Mount Kilimanjaro]] || {{convert|5895|m|disp=table}} || [[Tanzania]] || [[Lake Assal (Djibouti)|Lake Assal]] || {{convert|-155|m|disp=table}} || [[Djibouti]]
|-
| Europe || [[Mount Elbrus]] || {{convert|5642|m|disp=table}} || Russia || [[Caspian Sea]] || {{convert|-28|m|disp=table}} || Russia
|-
| Antarctica || [[Vinson Massif]] || {{convert|4892|m|disp=table}} || (none)|| Deep Lake, [[Vestfold Hills]] † || {{convert|-50|m|disp=table}} || (none)
|-
| Australia || [[Puncak Jaya]] || {{convert|4884|m|disp=table}} || [[Indonesia]] ([[Papua (province)|Papua]]) || [[Lake Eyre]] || {{convert|-15|m|disp=table}} || Australia
|}

† The lowest exposed points are given for North America and Antarctica. The lowest non-submarine bedrock elevations in these continents are the trough beneath [[Jakobshavn Glacier]] ({{convert|-1512|m}}<ref>Plummer, Joel. [https://www.cresis.ku.edu/~plummer/jakob.html#Bed_1 Jakobshavn Bed Elevation] {{webarchive|url=https://web.archive.org/web/20100627071506/https://www.cresis.ku.edu/~plummer/jakob.html |date=27 June 2010 }}, Center for the Remote Sensing of the Ice Sheets, Dept of Geography, University of Kansas.</ref>) and [[Bentley Subglacial Trench]] ({{convert|-2540|m}}), but these are covered by kilometers of ice.

Some sources list the [[Kuma–Manych Depression]] (a remnant of the [[Paratethys]]) as the geological border between Europe and Asia. This would place the Caucasus outside of Europe, thus making [[Mont Blanc]] (elevation 4810 m) in the [[Graian Alps]] the highest point in Europe - the lowest point would still be the shore of the Caspian Sea.

== Other divisions ==

=== Supercontinents ===
Aside from the conventionally known continents, the scope and meaning of the term ''continent'' varies. [[Supercontinent]]s, largely in evidence earlier in the geological record, are landmasses that comprise more than one [[craton]] or continental core. These have included [[Laurasia]], [[Gondwana]], [[Vaalbara]], [[Kenorland]], [[Columbia (supercontinent)|Columbia]], [[Rodinia]], and [[Pangaea]].

=== Subcontinents ===
Certain parts of continents are recognized as subcontinents, especially the large peninsulas separated from the main continental landmass by geographical features. The most notable examples are the [[Indian subcontinent]] and the [[Arabian Peninsula]].<ref name="Baldwin">{{citation |last=Baldwin |first=James A. |chapter=Continents |editor=R. W. McColl |title=Encyclopedia of World Geography |url=https://books.google.com/books?id=DJgnebGbAB8C&pg=PA215 |date=14 May 2014 |publisher=Infobase Publishing |isbn=978-0-8160-7229-3 |page=215}}</ref> The southern cone of South America and [[Alaska|Alaskan peninsula]] of North America are other examples.<ref name="Baldwin"/>

In many of these cases, the "subcontinents" concerned are on different [[plate tectonics|tectonic plates]] from the rest of the continent, providing a geological justification for the terminology.<ref name="Molnar2015">{{citation|last=Molnar|first=Peter|title=Plate Tectonics: A Very Short Introduction|url=https://books.google.com/books?id=FbuUBgAAQBAJ&pg=PA116|date=26 March 2015|publisher=OUP Oxford|isbn=978-0-19-104396-3}}
* p. 98: Thus, we can calculate past positions of the India plate, with the Indian subcontinent as its passenger, with respect to the Eurasia plate.
* p. 116: The Arabian subcontinent later, approximately 35 million years ago, collided with southern Eurasia to form the Zagros Mountains of southwestern Iran.
</ref> [[Greenland]], generally reckoned as the [[List of islands by area|world's largest island]] on the northeastern periphery of the [[North American Plate]], is sometimes referred to as a subcontinent.<ref>{{citation|title=Nares Strait and the drift of Greenland: a conflict in plate tectonics|url=https://books.google.com/books?id=9prkteX0EdsC&pg=PA32|publisher=Museum Tusculanum Press|isbn=978-87-635-1150-6|pages=32–}}</ref><ref name="FarmerCook2013">{{citation|last1=Farmer|first1=G. Thomas|last2=Cook|first2=John|title=Climate Change Science: A Modern Synthesis: Volume 1 - The Physical Climate|url=https://books.google.com/books?id=tbtEAAAAQBAJ&pg=PA281|date=12 January 2013|publisher=Springer Science & Business Media|isbn=978-94-007-5757-8|pages=281–}}</ref> This is a significant departure from the more conventional view of a subcontinent as comprising a very large peninsula on the fringe of a continent.

Where the Americas are viewed as a single continent (America), it is divided into two subcontinents ([[North America]] and [[South America]])<ref name="Gallay2015">{{citation|last=Gallay|first=Alan|title=Colonial Wars of North America, 1512-1763 (Routledge Revivals): An Encyclopedia|url=https://books.google.com/books?id=jmnbCQAAQBAJ&pg=PA204|date=11 June 2015|publisher=Routledge|isbn=978-1-317-48719-7|pages=204–}}</ref><ref name="InnesHaron2000">{{citation|last1=Innes|first1=John L.|last2=Haron|first2=Abu Hassan|title=Air Pollution and the Forests of Developing and Rapidly Industrializing Regions|url=https://books.google.com/books?id=2qOXUQ21zb4C&pg=PA36|year=2000|publisher=CABI|isbn=978-0-85199-932-6|pages=36–}}</ref><ref name="Vivares2014">{{citation|last=Vivares|first=Dr Ernesto|title=Exploring the New South American Regionalism (NSAR)|url=https://books.google.com/books?id=Pab8AgAAQBAJ&pg=PA40|date=28 March 2014|publisher=Ashgate Publishing, Ltd.|isbn=978-1-4094-6961-2|pages=40–}}</ref> or three (with [[Central America]] being the third).<ref name="Leonard2005">{{citation|last=Leonard|first=Thomas M.|title=Encyclopedia of the Developing World|url=https://books.google.com/books?id=3mE04D9PMpAC&pg=PA1637|date=October 2005|publisher=Psychology Press|isbn=978-1-57958-388-0|pages=1637–}}</ref><ref>In Ibero-America, North America usually designates a region (''subcontinente'' in Spanish) of the Americas containing Canada, the United States, and Mexico, and often Greenland, Saint Pierre and Miquelon, and Bermuda; the land bridge of Central America is generally considered a subregion of North America.[http://mx.encarta.msn.com/encyclopedia_761562468/Norteam%C3%A9rica.html Norteamérica (Mexican version)] {{webarchive |url=https://web.archive.org/web/20090130000000/http://mx.encarta.msn.com/encyclopedia_761562468/Norteam%C3%A9rica.html |date=30 January 2009 }}/[http://es.encarta.msn.com/encyclopedia_761562468/Norteam%C3%A9rica.html (Spaniard version)]. ''Encarta Online Encyclopedia.''. [https://www.webcitation.org/5kwRLFsmt?url=http://es.encarta.msn.com/encyclopedia_761562468/Norteam%C3%A9rica.html Archived] 2009-10-31.</ref> When Eurasia is regarded as a single continent, Europe is treated as a subcontinent.<ref name="Baldwin"/>

=== Submerged continents ===
Some areas of [[continental crust]] are largely covered by the sea and may be considered [[submerged continent]]s. Notable examples are [[Zealandia]], emerging from the sea primarily in [[New Zealand]] and [[New Caledonia]], and the almost completely submerged [[Kerguelen Plateau]] in the southern [[Indian Ocean]].

=== Microcontinents ===
Some islands lie on sections of continental crust that have rifted and drifted apart from a main continental landmass. While not considered continents because of their relatively small size, they may be considered [[continental fragment|microcontinents]]. [[Madagascar]], the largest example, is usually considered an island of Africa but has been referred to as "the eighth continent" from a {{clarify|text=biological perspective|date=March 2016}}.<ref>{{Cite book | last1 = Hillstrom | first1 = Kevin | last2 = Collier Hillstrom | first2 =Laurie | title = Africa and the Middle East: a continental overview of environmental issues | publisher = ABC-CLIO | location = Santa Barbara, CA | year = 2003 | page = 50 | isbn = 978-1-57607-688-0 |url = https://books.google.com/books?id=XxIk9zTm_e8C&printsec=frontcover#v=onepage&q&f=false}}</ref>

=== Botanical continents ===
[[File:WGSRPD World.svg|thumb|300px|"Botanical continents" defined by the [[World Geographical Scheme for Recording Plant Distributions]].]]

"Continents" may be defined differently for specific purposes. The [[Biodiversity Information Standards]] organization has developed the [[World Geographical Scheme for Recording Plant Distributions]], used in many international plant databases. This scheme divides the world into nine "botanical continents". Some match the traditional geographical continents, but some differ significantly. Thus the Americas are divided between Northern America (Mexico northwards) and Southern America (Central America and the Caribbean southwards) rather than between North America and South America.<ref>{{cite book |last=Brummitt |first=R.K. |year=2001 |title=World Geographical Scheme for Recording Plant Distributions: Edition 2 |publisher=International Working Group on Taxonomic Databases For Plant Sciences (TDWG) |url = http://www.nhm.ac.uk/hosted_sites/tdwg/TDWG_geo2.pdf |accessdate = 2006-11-27 |ref=harv}}</ref>

== History of continental configurations ==
{{main article|Geological history of the Earth}}

== History of the concept ==
[[File:Strabo.jpg|thumb|left|187px|The Ancient Greek geographer [[Strabo]] holding a globe showing ''Europa'' and ''Asia'']]

=== Early concepts of the Old World continents ===
The first distinction between continents was made by [[ancient Greece|ancient Greek]] mariners who gave the names Europe and Asia to the lands on either side of the waterways of the [[Aegean Sea]], the [[Dardanelles]] strait, the [[Sea of Marmara]], the [[Bosporus]] strait and the [[Black Sea]].<ref name=Toynbee>[[Arnold J. Toynbee|Toynbee, Arnold J.]] (1954). ''A Study of History''. London: Oxford University Press, v. 8, pp. 711-12.</ref> The names were first applied just to lands near the coast and only later extended to include the hinterlands.<ref>{{cite book |last=Tozer |first=H. F. |title=A History of Ancient Geography |year=1897 |publisher=University Press |location=Cambridge |page= 69}}</ref> But the division was only carried through to the end of navigable waterways and "... beyond that point the Hellenic geographers never succeeded in laying their finger on any inland feature in the physical landscape that could offer any convincing line for partitioning an indivisible Eurasia ..."<ref name=Toynbee/>

Ancient Greek thinkers subsequently debated whether Africa (then called ''Libya'') should be considered part of Asia or a third part of the world. Division into three parts eventually came to predominate.<ref>{{cite book |last=Tozer |first=H. F. |title=A History of Ancient Geography |year=1897 |publisher=University Press |location=Cambridge |page= 67}}</ref> From the Greek viewpoint, the Aegean Sea was the center of the world; Asia lay to the east, Europe to the north and west, and Africa to the south.{{sfnp|Lewis & Wigen, The Myth of Continents|1997 |pp=21–22}} The boundaries between the continents were not fixed. Early on, the Europe–Asia boundary was taken to run from the Black Sea along the [[Rioni River]] (known then as the ''Phasis'') in [[Georgia (country)|Georgia]]. Later it was viewed as running from the Black Sea through [[Kerch Strait]], the [[Sea of Azov]] and along the [[Don River, Russia|Don River]] (known then as the ''Tanais'') in [[Russia]].<ref>{{cite book |last=Tozer |first=H. F. |title=A History of Ancient Geography |year=1897 |publisher=University Press |location=Cambridge |page= 68}}</ref> The boundary between Asia and Africa was generally taken to be the [[Nile]] River. [[Herodotus]]<ref>[[Herodotus]]. Translated by George Rawlinson (2000). ''[[Histories (Herodotus)|The Histories of Herodotus of Halicarnassus]]'' [http://www.omphaloskepsis.com/ebooks/pdf/hrdts.pdf]. Ames, Iowa: Omphaloskepsis, book 2, p. 18. {{webarchive |url=https://web.archive.org/web/20060819160734/http://www.omphaloskepsis.com/ebooks/pdf/hrdts.pdf |date=19 August 2006 }}</ref> in the 5th century BC, however, objected to the unity of [[Egypt]] being split into Asia and Africa ("Libya") and took the boundary to lie along the western border of Egypt, regarding Egypt as part of Asia. He also questioned the division into three of what is really a single landmass,<ref>[[Herodotus]]. Translated by George Rawlinson (2000). ''[[Histories (Herodotus)|The Histories of Herodotus of Halicarnassus]]'' {{cite web|url=http://www.omphaloskepsis.com/ebooks/pdf/hrdts.pdf |title=Archived copy |accessdate=2016-02-08 |deadurl=yes |archiveurl=https://web.archive.org/web/20060819160734/http://www.omphaloskepsis.com/ebooks/pdf/hrdts.pdf |archivedate=19 August 2006 |df=dmy }}. Ames, Iowa: Omphaloskepsis, book 4, p. 38. "I cannot conceive why three names ... should ever have been given to a tract which is in reality one,"</ref> a debate that continues nearly two and a half millennia later.

[[Eratosthenes]], in the 3rd century BC, noted that some geographers divided the continents by rivers (the Nile and the Don), thus considering them "islands". Others divided the continents by [[isthmus]]es, calling the continents "peninsulas". These latter geographers set the border between Europe and Asia at the isthmus between the Black Sea and the [[Caspian Sea]], and the border between Asia and Africa at the isthmus between the [[Red Sea]] and the mouth of [[Lake Bardawil]] on the [[Mediterranean Sea]].<ref>[[Strabo]]. Translated by Horace Leonard Jones (1917). ''[[Geographica|Geography]]''.[http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Strabo/] Harvard University Press, book 1, ch. 4.[http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Strabo/1D*.html]</ref>
[[File:T and O map Guntherus Ziner 1472.jpg|thumb|Medieval [[T and O map]] showing the three continents as domains of the sons of [[Noah]]—Asia to Sem ([[Shem]]), Europe to Iafeth ([[Japheth]]), and Africa to Cham ([[Ham, son of Noah|Ham]]).]]

Through the Roman period and the [[Middle Ages]], a few writers took the [[Isthmus of Suez]] as the boundary between Asia and Africa, but most writers continued to consider it the Nile or the western border of Egypt (Gibbon){{citation needed|date=October 2014}}. In the Middle Ages, the world was usually portrayed on [[T and O map]]s, with the T representing the waters dividing the three continents. By the middle of the 18th century, "the fashion of dividing Asia and Africa at the Nile, or at the Great Catabathmus [the boundary between Egypt and [[Libya]]] farther west, had even then scarcely passed away".<ref>Goddard, Farley Brewer (1884). "Researches in the Cyrenaica". ''The American Journal of Philology'', 5 (1) p. 38.</ref>

=== European arrival in the Americas ===
[[Christopher Columbus]] sailed across the [[Atlantic Ocean]] to the [[Caribbean|West Indies]] in 1492, sparking a period of European exploration of the [[Americas]]. But despite four voyages to the Americas, Columbus never believed he had reached a new continent—he always thought it was part of Asia.

In 1501, [[Amerigo Vespucci]] and [[Gonçalo Coelho]] attempted to sail around what they considered the southern end of the Asian mainland into the [[Indian Ocean]], passing through [[Fernando de Noronha]]. After reaching the coast of [[Brazil]], they sailed a long way further south along the coast of [[South America]], confirming that this was a land of continental proportions and that it also extended much further south than Asia was known to.<ref name=OGorman>{{cite book | last = O'Gorman | first = Edmundo | authorlink = Edmundo O'Gorman | title = The Invention of America | publisher = Indiana University Press | year= 1961 | pages = 106–112}}</ref> On return to Europe, an account of the voyage, called ''Mundus Novus'' ("New World"), was published under Vespucci's name in 1502 or 1503,<ref name=formisano1>Formisano, Luciano (Ed.) (1992). ''Letters from a New World: Amerigo Vespucci's Discovery of America''. New York: Marsilio, pp. xx-xxi. {{ISBN|0-941419-62-2}}.</ref> although it seems that it had additions or alterations by another writer.<ref name=Zerubavel1>Zerubavel, Eviatar (2003). ''Terra Cognita: The Mental Discovery of America''. New Brunswick: Transaction Publishers, pp. 77–79. {{ISBN|0-7658-0987-7}}.</ref> Regardless of who penned the words, ''Mundus Novus'' credited Vespucci with saying, "I have discovered a continent in those southern regions that is inhabited by more numerous people and animals than our Europe, or Asia or Africa",<ref name=formisano2>Formisano, Luciano (Ed.) (1992). ''Letters from a New World: Amerigo Vespucci's Discovery of America''. New York: Marsilio, p. 45. {{ISBN|0-941419-62-2}}.</ref> the first known explicit identification of part of the Americas as a continent like the other three.

Within a few years the name "New World" began appearing as a name for South America on world maps, such as the Oliveriana (Pesaro) map of around 1504–1505. Maps of this time though, still showed [[North America]] connected to Asia and showed South America as a separate land.<ref name=Zerubavel1/>

[[File:Waldseemuller map 2.jpg|thumb|left|375px|''Universalis Cosmographia'', Waldseemüller's 1507 world map—the first to show the Americas separate from Asia]]

In 1507 [[Martin Waldseemüller]] published a world map, ''[[Waldseemüller map|Universalis Cosmographia]]'', which was the first to show North and South America as separate from Asia and surrounded by water. A small inset map above the main map explicitly showed for the first time the Americas being east of Asia and separated from Asia by an ocean, as opposed to just placing the Americas on the left end of the map and Asia on the right end. In the accompanying book ''[[Cosmographiae Introductio]]'', Waldseemüller noted that the earth is divided into four parts, Europe, Asia, Africa and the fourth part, which he named "America" after Amerigo Vespucci's first name.<ref name=Zerubavel2>Zerubavel, Eviatar (2003). ''Terra Cognita: The Mental Discovery of America''. New Brunswick: Transaction Publishers, pp. 80–82. {{ISBN|0-7658-0987-7}}.</ref> On the map, the word "America" was placed on part of South America.

=== The word ''continent'' ===
From the 16th century the English noun ''continent'' was derived from the term ''continent land'', meaning continuous or connected land<ref name=oed>"continent n." (1989) ''[[Oxford English Dictionary]]'', 2nd edition. [[Oxford University Press]].</ref> and translated from the Latin ''terra continens''.<ref>"continent1 n." (2006) ''The [[Concise Oxford English Dictionary]]'', 11th edition revised. (Ed.) Catherine Soanes and Angus Stevenson. [[Oxford University Press]].</ref> The noun was used to mean "a connected or continuous tract of land" or [[mainland]].<ref name=oed/> It was not applied only to very large areas of land—in the 17th century, references were made to the ''continents'' (or mainlands) of [[Isle of Man]], [[Ireland]] and [[Wales]] and in 1745 to [[Sumatra]].<ref name=oed/> The word ''continent'' was used in translating Greek and Latin writings about the three "parts" of the world, although in the original languages no word of exactly the same meaning as ''continent'' was used.{{sfnp|Lewis & Wigen, The Myth of Continents|1997|p=29}}

While ''continent'' was used on the one hand for relatively small areas of continuous land, on the other hand geographers again raised Herodotus's query about why a single large landmass should be divided into separate continents. In the mid-17th century, [[Peter Heylin]] wrote in his ''Cosmographie'' that "A Continent is a great quantity of Land, not separated by any Sea from the rest of the World, as the whole Continent of Europe, Asia, Africa." In 1727, [[Ephraim Chambers]] wrote in his ''Cyclopædia,'' "The world is ordinarily divided into two grand continents: the [[Old World|old]] and the [[New World|new]]." And in his 1752 atlas, [[Emanuel Bowen]] defined a continent as "a large space of dry land comprehending many countries all joined together, without any separation by water. Thus Europe, Asia, and Africa is one great continent, as America is another."<ref>Bowen, Emanuel. (1752). ''A Complete Atlas, or Distinct View of the Known World''. London, p. 3.</ref> However, the old idea of Europe, Asia and Africa as "parts" of the world ultimately persisted with these being regarded as separate continents.

[[File:Thevenot - Hollandia Nova detecta 1644.png|thumb|right|250px|''Hollandia Nova'', 1659 map prepared by [[Joan Blaeu]] based on voyages by [[Abel Tasman]] and [[Willem Jansz]], this image shows a French edition of 1663]]

=== Beyond four continents ===
From the late 18th century, some geographers started to regard North America and South America as two parts of the world, making five parts in total. Overall though, the fourfold division prevailed well into the 19th century.<ref name=lewis30>{{harvp|Lewis & Wigen, The Myth of Continents|1997|p=30}}</ref>

Europeans discovered [[Australia (continent)|Australia]] in 1606, but for some time it was taken as part of Asia. By the late 18th century, some geographers considered it a continent in its own right, making it the sixth (or fifth for those still taking America as a single continent).<ref name=lewis30/> In 1813, [[Samuel Butler (schoolmaster)|Samuel Butler]] wrote of Australia as "[[New Holland (Australia)|New Holland]], an immense island, which some geographers dignify with the appellation of another continent" and the ''[[Oxford English Dictionary]]'' was just as equivocal some decades later.<ref>"continent n. 5. a." (1989) ''[[Oxford English Dictionary]]'', 2nd edition. [[Oxford University Press]]. "the great island of Australia is sometimes reckoned as another [continent]"</ref>

[[Antarctica]] was sighted in 1820 during the [[First Russian Antarctic Expedition]] and described as a continent by [[Charles Wilkes]] on the [[United States Exploring Expedition]] in 1838, the last continent identified, although a great "Antarctic" (antipodean) landmass had been anticipated for millennia. An 1849 atlas labelled Antarctica as a continent but few atlases did so until after [[World War II]].<ref>{{cite book |last=Lewis |first=Martin W. |authorlink= |author2=Kären E. Wigen |title=The Myth of Continents: a Critique of Metageography |year=1997 |publisher=University of California Press |location=Berkeley |isbn=0-520-20743-2 |chapter= |quote= }}</ref>

From the mid-19th century, atlases published in the United States more commonly treated North and South America as separate continents, while atlases published in Europe usually considered them one continent. However, it was still not uncommon for American atlases to treat them as one continent up until World War II.<ref name=lewis32>{{cite book |last=Lewis |first=Martin W. |authorlink= |author2=Kären E. Wigen |title=The Myth of Continents: a Critique of Metageography |year=1997 |publisher=University of California Press |location=Berkeley |id={{ISBN|0-520-20742-4}}, {{ISBN|0-520-20743-2}} |page=32 |chapter= |quote= }}</ref>

From the 1950s, most U.S. geographers divided the Americas into two continents.<ref name=lewis32/> With the addition of Antarctica, this made the seven-continent model. However, this division of the Americas never appealed to [[Latin America]]ns, who saw their region spanning an {{lang|es|''América''}} as a single landmass, and there the conception of six continents remains, as it does in scattered other countries.{{citation needed|date=December 2012}}

Some geographers regard Europe and Asia together as a single continent, dubbed ''[[Eurasia]]''.<ref>''Some geographers list only six continents, combining Europe and Asia into Eurasia. In parts of the world, students learn that there are just five continents: Eurasia, Australia, Africa, Antarctica, and the Americas.''{{cite web|url=http://www.nationalgeographic.com/faq/geography.html#continents|title=How many continents are there?|publisher=[[National Geographic Society]]|accessdate=2010-09-26}}</ref> In this model, the world is divided into six continents, with North America and South America considered separate continents.

== Geology ==
{{refimprove section|date=May 2015}}
{{further information|Continental crust|Plate tectonics}}
Geologists use the term ''continent'' in a different manner from geographers, where a continent is defined by continental crust: a platform of [[metamorphic rock|metamorphic]] and [[igneous rock]], largely of [[granite|granitic]] composition. Some geologists restrict the term 'continent' to portions of the crust built around stable [[Precambrian]] "shield", typically 1.5 to 3.8 billion years old, called a [[craton]]. The craton itself is an [[accretion (geology)|accretionary]] complex of ancient mobile belts (mountain belts) from earlier cycles of [[subduction]], [[continental collision]] and break-up from plate tectonic activity. An outward-thickening veneer of younger, minimally deformed [[sedimentary rock]] covers much of the craton. The margins of geologic continents are characterized by currently active or relatively recently active mobile belts and deep troughs of accumulated marine or [[river delta|deltaic]] [[sediment]]s. Beyond the margin, there is either a [[continental shelf]] and drop off to the [[basalt]]ic [[oceanic basin|ocean basin]] or the margin of another continent, depending on the current plate-tectonic setting of the continent. A continental boundary does not have to be a body of water. Over geologic time, continents are periodically submerged under large epicontinental seas, and continental collisions result in a continent becoming attached to another continent. The current geologic era is relatively anomalous in that so much of the continental areas are "high and dry"; that is, many parts of the continents that were once below sea level are now elevated well above it due to changes in sea levels and the subsequent uplifting of those continental areas from tectonic activity.<ref>{{Cite book|title = Encyclopedia of Ocean Sciences|last = Kominz|first = Michelle A.|publisher = Academic Press|year = 2001|isbn = |location = San Diego|pages = 2609|chapter = Sea level variations over geologic time|url = http://www.curry.eas.gatech.edu/Courses/6140/ency/Chapter10/Ency_Oceans/Sea_Level_Variations.pdf}}</ref>

[[File:Plates tect2 en.svg|thumb|left|350px|The tectonic plates underlying the continents and oceans]]

Some argue that continents are accretionary crustal "rafts" that, unlike the denser basaltic crust of the ocean basins, are not subjected to destruction through the plate tectonic process of subduction. This accounts for the great age of the rocks comprising the continental cratons. By this definition, Eastern Europe, India and some other regions could be regarded as continental masses distinct from the rest of Eurasia because they have separate ancient shield areas (i.e. [[East European craton]] and [[Indian craton]]). Younger mobile belts (such as the [[Ural Mountains]] and [[Himalayas]]) mark the boundaries between these regions and the rest of Eurasia.

There are many [[Continental fragment|microcontinents, or continental fragments]], that are built of continental crust but do not contain a craton. Some of these are fragments of [[Gondwana]] or other ancient cratonic continents: [[Zealandia (continent)|Zealandia]], which includes [[Geography of New Zealand|New Zealand]] and [[Geography of New Caledonia|New Caledonia]]; [[Geography of Madagascar|Madagascar]]; the northern [[Mascarene Plateau]], which includes the [[Seychelles]]. Other islands, such as several in the [[Caribbean Sea]], are composed largely of granitic rock as well, but all continents contain both granitic and basaltic crust, and there is no clear boundary as to which islands would be considered microcontinents under such a definition. The [[Kerguelen Plateau]], for example, is largely volcanic, but is associated with the breakup of Gondwanaland and is considered a microcontinent,<ref>{{cite web|url=http://www.utexas.edu/opa/news/99newsreleases/nr_199905/nr_continent990528.html |title=UT Austin scientist plays major rule in study of underwater "micro-continent" |publisher=Utexas.edu |accessdate=2012-08-26 |deadurl=yes |archiveurl=https://web.archive.org/web/20071103165732/http://www.utexas.edu/opa/news/99newsreleases/nr_199905/nr_continent990528.html |archivedate= 3 November 2007 |df= }}</ref><ref>{{cite news|url=http://news.bbc.co.uk/1/hi/sci/tech/353277.stm |title=Sci/Tech | 'Lost continent' discovered |publisher=BBC News |date=1999-05-27 |accessdate=2012-08-26}}</ref> whereas volcanic [[Geography of Iceland|Iceland]] and [[Hawaiian Islands|Hawaii]] are not. The [[British Isles]], [[Sri Lanka]], [[Borneo]], and [[Newfoundland (island)|Newfoundland]] are margins of the [[Laurasia]]n continent—only separated by inland seas flooding its margins.

[[Plate tectonics]] offers yet another way of defining continents. Today, Europe and most of Asia constitute the unified [[Eurasian Plate]], which is approximately coincident with the geographic Eurasian continent excluding India, Arabia, and far eastern Russia. India contains a central shield, and the geologically recent [[Himalaya]] mobile belt forms its northern margin. North America and South America are separate continents, the connecting [[isthmus]] being largely the result of [[volcano|volcanism]] from relatively recent subduction tectonics. North American continental rocks extend to Greenland (a portion of the [[Canadian Shield]]), and in terms of plate boundaries, the North American plate includes the easternmost portion of the Asian land mass. Geologists do not use these facts to suggest that eastern Asia is part of the North American continent, even though the plate boundary extends there; the word continent is usually used in its geographic sense and additional definitions ("continental rocks," "plate boundaries") are used as appropriate.

The movement of plates has caused the formation and break-up of continents over time, including occasional formation of a supercontinent that contains most or all of the continents. The supercontinent [[Columbia (supercontinent)|Columbia]] or Nuna formed during a period of 2.0–1.8 billion years and broke up about 1.5–1.3 billion years ago.<ref name="Zhao1">{{Cite journal |last1=Zhao |first1=Guochun |last2=Cawood |first2=Peter A. |last3=Wilde |first3=Simon A. |last4=Sun |first4=M. |date=November 2002 |title=Review of global 2.1–1.8 Ga orogens: implications for a pre-Rodinia supercontinent |journal=Earth-Science Reviews |volume=59 |pages=125–162 |doi=10.1016/S0012-8252(02)00073-9 |bibcode=2002ESRv...59..125Z |url=http://www.sciencedirect.com/science/article/pii/S0012825202000739 |accessdate=2013-01-07}}</ref><ref name="Zhao2">{{Cite journal |first=Guochun |last=Zhao |author2=Sun, M. |author3=Wilde, Simon A. |author4= Li, S.Z. |date=November 2004 |title=A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup |journal=Earth-Science Reviews |volume=67 |pages=91–123 |accessdate=2013-01-08 |doi=10.1016/j.earscirev.2004.02.003 |bibcode=2004ESRv...67...91Z|url=http://www.sciencedirect.com/science/article/pii/S0012825204000182}}</ref> The supercontinent [[Rodinia]] is thought to have formed about 1 billion years ago and to have embodied most or all of Earth's continents, and broken up into eight continents around 600 million years ago. The eight continents later re-assembled into another supercontinent called [[Pangaea]]; Pangaea broke up into Laurasia (which became North America and Eurasia) and Gondwana (which became the remaining continents).

== See also ==
* [[List of continent name etymologies]]
* [[List of sovereign states and dependent territories by continent]]
* [[List of supercontinents]]
* [[List of transcontinental countries]]
* [[Lists of cities]]
* [[Subregion]]
* [[Continental Europe]]
* {{Books-inline|Continents}}

== References ==
{{Reflist|30em}}

== Bibliography ==
* {{cite book|last1=Lewis |first1=Martin W. |first2=Kären E. |last2=Wigen |authorlink2 = Kären Wigen|title=The Myth of Continents: a Critique of Metageography |year=1997 |publisher=University of California Press |location=Berkeley |id={{ISBN|0-520-20742-4}}, {{ISBN|0-520-20743-2}} |url=https://books.google.com/books?id=C2as0sWxFBAC |ref={{sfnref|Lewis & Wigen, The Myth of Continents|1997}}}}

== External links ==
{{Wikidata property |P30 |continent }}
{{Commons+cat|Continents|Continents}}
* [https://www.youtube.com/watch?v=3uBcq1x7P34 "What are continents?"] [[YouTube]] video by [[CGP Grey]]
* {{Cite EB1911|wstitle=Continent |short=x}}

{{Physical Earth}}
{{Continents of the world}}
{{Regions of the world}}
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[[Category:Continents|*]]

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