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Continent

Continent

Overview
A continent is one of several very large landmass
Landmass
A landmass is a contiguous area of land surrounded by ocean. Although it may be most often written as one word to distinguish it from the usage "land mass"—the measure of land area—it is also used as two words.Landmasses include:*supercontinents...

es on Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. They are generally identified by convention
Convention (norm)
A convention is a set of agreed, stipulated or generally accepted standards, norms, social norms or criteria, often taking the form of a custom....

 rather than any strict criteria, with seven regions commonly regarded as continents—they are (from largest in size to smallest): Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, Antarctica, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, and Australia
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

.

Plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

 is the geological
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 process and study of the movement, collision and division of continents, earlier known as continental drift
Continental drift
Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912...

.

For people in Britain and Ireland, in spite of being a part of Europe themselves, the expression "the Continent" may also refer to Continental Europe
Continental Europe
Continental Europe, also referred to as mainland Europe or simply the Continent, is the continent of Europe, explicitly excluding European islands....

, that is, the mainland of Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, excluding the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

, Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 and some other islands.

Conventionally, "continents are understood to be large, continuous, discrete masses of land, ideally separated by expanses of water." Many of the seven most commonly recognized continents identified by convention are not discrete landmasses separated by water.
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Encyclopedia
A continent is one of several very large landmass
Landmass
A landmass is a contiguous area of land surrounded by ocean. Although it may be most often written as one word to distinguish it from the usage "land mass"—the measure of land area—it is also used as two words.Landmasses include:*supercontinents...

es on Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. They are generally identified by convention
Convention (norm)
A convention is a set of agreed, stipulated or generally accepted standards, norms, social norms or criteria, often taking the form of a custom....

 rather than any strict criteria, with seven regions commonly regarded as continents—they are (from largest in size to smallest): Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, Antarctica, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, and Australia
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

.

Plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

 is the geological
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 process and study of the movement, collision and division of continents, earlier known as continental drift
Continental drift
Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912...

.

For people in Britain and Ireland, in spite of being a part of Europe themselves, the expression "the Continent" may also refer to Continental Europe
Continental Europe
Continental Europe, also referred to as mainland Europe or simply the Continent, is the continent of Europe, explicitly excluding European islands....

, that is, the mainland of Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, excluding the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

, Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 and some other islands.

Definitions and application


Conventionally, "continents are understood to be large, continuous, discrete masses of land, ideally separated by expanses of water." Many of the seven most commonly recognized continents identified by convention are not discrete landmasses separated by water. The criterion "large" leads to arbitrary classification: Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

, with a surface area of 2166086 sqkm is considered the world's largest island, while Australia, at 7617930 sqkm is deemed to be a continent. Likewise, the ideal criterion that each be a continuous landmass is often disregarded by the inclusion of the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

 and oceanic islands, and contradicted by classifying North and South America as two continents; and/or Eurasia and Africa as two continents, with no natural separation by water. This anomaly reaches its extreme if the continuous land mass of Europe and Asia is considered to constitute two continents. The Earth's major landmasses are washed upon by a single, continuous world ocean
World Ocean
The World Ocean, world ocean, or global ocean, is the interconnected system of the Earth's oceanic waters, and comprises the bulk of the hydrosphere, covering almost 71% of the Earth's surface, with a total volume of 1.332 billion cubic kilometres.The unity and continuity of the World Ocean, with...

, which is divided into a number of principal ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

ic components by the continents and various geographic criteria.

Extent of continents


The narrowest meaning of continent is that of a continuous 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
Continental Europe
Continental Europe, also referred to as mainland Europe or simply the Continent, is the continent of Europe, explicitly excluding European islands....

is used to refer to mainland Europe, excluding island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

s such as Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

, Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

, and Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

, and the term continent of Australia may refer to the mainland of Australia
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

, excluding Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

 and New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...

. Similarly, the continental United States refers to the 48 contiguous states in central North America and may include Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 in the northwest of the continent (the two being separated by Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

), while excluding Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

 in the middle of the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

.

From the perspective of geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 or physical geography
Physical geography
Physical geography is one of the two major subfields of geography. Physical geography is that branch of natural science which deals with the study of processes and patterns in the natural environment like the atmosphere, biosphere and geosphere, as opposed to the cultural or built environment, the...

, continent may be extended beyond the confines of continuous dry land to include the shallow, submerged adjacent area (the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

) and the islands on the shelf (continental islands), as they are structurally part of the continent. From this perspective the edge of the continental shelf is the true edge of the continent, as shorelines vary with changes in sea level. 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.

As a cultural construct, the concept of a continent may go beyond the continental shelf to include oceanic islands and continental fragments. In this way, Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 is considered part of Europe and Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

 part of Africa. Extrapolating the concept to its extreme, some geographers group the Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...

n continental plate with other islands in the Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 into one continent called Oceania
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...

. This allows the entire land surface of the Earth to be divided into continents or quasi-continents.

Separation of continents



The ideal criterion that each continent be a discrete landmass is commonly disregarded in favor of more arbitrary, historical conventions. Of the seven most commonly recognized continents, only Antarctica and Australia are distinctly separated from other continents.

Several continents are defined not as absolutely distinct bodies but as "more or less discrete masses of land". Asia and Africa are joined by the Isthmus of Suez
Isthmus of Suez
The Isthmus of Suez is the narrow strip land that lies between the Mediterranean Sea and the Red Sea, linking the continents of Africa and Asia. It contains the country of Egypt and the Suez Canal. Like many isthmuses, it is a location of great strategic value....

, and North and South America by the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...

. Both these isthmus
Isthmus
An isthmus is a narrow strip of land connecting two larger land areas usually with waterforms on either side.Canals are often built through isthmuses where they may be particularly advantageous to create a shortcut for marine transportation...

es are very narrow in comparison with the bulk of the landmasses they join, and both are transected by artificial canals (the Suez
Suez Canal
The Suez Canal , also known by the nickname "The Highway to India", is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea and the Red Sea. Opened in November 1869 after 10 years of construction work, it allows water transportation between Europe and Asia without navigation...

 and Panama canal
Panama Canal
The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...

s, respectively) which effectively separate these landmasses.

The division of the landmass of Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

 into the continents of Asia and Europe is an anomaly, as no sea separates them. An alternative view, that Eurasia is a single continent, results in a six-continent view of the world. This view is held by some geographers, including some in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 (which spans Asia and Europe), some East European countries and by some in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

. The separation of Eurasia into Europe and Asia is viewed by some as a residue of Eurocentrism
Eurocentrism
Eurocentrism is the practice of viewing the world from a European perspective and with an implied belief, either consciously or subconsciously, in the preeminence of European culture...

: "In physical, cultural and historical diversity, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 and India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 are comparable to the entire European landmass, not to a single European country. A better (if still imperfect) analogy would compare France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, not to India as a
whole, but to a single Indian state, such as Uttar Pradesh
Uttar Pradesh
Uttar Pradesh abbreviation U.P. , is a state located in the northern part of India. With a population of over 200 million people, it is India's most populous state, as well as the world's most populous sub-national entity...

." However, for historical and cultural reasons, the view of Europe as a separate continent continues in several categorizations.

North America and South America are now treated as separate continents. However, in earlier times they were viewed as a single continent known as America, with this viewpoint remaining common in the United States until World War II. This remains the more common vision in Spain, Portugal and Latin American countries, where they are taught as a single continent. This use is shown in names such as the Organization of American States
Organization of American States
The Organization of American States is a regional international organization, headquartered in Washington, D.C., United States...

. From the 19th century some people used the term "Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

" to avoid ambiguity with the United States of America.

When continents are defined as discrete landmasses, embracing all the contiguous land of a body, then Asia, Europe and Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 form a single continent known by various names such as Afro-Eurasia
Afro-Eurasia
Afro-Eurasia or less commonly Afrasia or Eurafrasia is the term used to describe the largest landmass on earth. It may be defined as a supercontinent, consisting of Africa and Eurasia...

. This produces a four-continent model consisting of Afro-Eurasia, America, Antarctica and Australia.

When sea levels were lower during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

, greater areas of continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

 were exposed as dry land, forming land bridge
Land bridge
A land bridge, in biogeography, is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonise new lands...

s. At this time Australia-New Guinea was a single, continuous continent. Likewise the Americas and Afro-Eurasia were joined by the Bering land bridge
Bering land bridge
The Bering land bridge was a land bridge roughly 1,000 miles wide at its greatest extent, which joined present-day Alaska and eastern Siberia at various times during the Pleistocene ice ages. Like most of Siberia and all of Manchuria, Beringia was not glaciated because snowfall was extremely light...

. Other islands such as Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 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 of continents


There are numerous ways of distinguishing the continents:

Models
Color-coded map showing the various continents. Similar shades exhibit areas that may be consolidated or subdivided.
7 continents
    North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

    South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

    Antarctica
    Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

    Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

    Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

    Australia
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

6 continents
    North America
    South America
    Antarctica
    Africa
       Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

    Australia
6 continents
       America
    Antarctica
    Africa
    Europe
    Asia
    Australia
5 continents
       America
    Antarctica
    Africa
       Eurasia
    Australia
4 continents
       America
    Antarctica
    style="background: #c10000;">       Afro-Eurasia
Afro-Eurasia
Afro-Eurasia or less commonly Afrasia or Eurafrasia is the term used to describe the largest landmass on earth. It may be defined as a supercontinent, consisting of Africa and Eurasia...

    Australia



The seven-continent model is usually taught in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 and most English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

-speaking countries. The six-continent combined-Eurasia model is sometimes preferred in the former states of the USSR  and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 . The six-continent combined-America model is sometimes taught in Latin America
Latin America
Latin America is a region of the Americas where Romance languages  – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...

  and in some parts of Europe including Greece (equivalent 5 inhabited continents model (i.e. excluding Antarctica) still also found in texts)
, Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

and Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

. Using this latter model as a starting point, the Olympics
International Olympic Committee
The International Olympic Committee is an international corporation based in Lausanne, Switzerland, created by Pierre de Coubertin on 23 June 1894 with Demetrios Vikelas as its first president...

 use only inhabited continents (excluding Antarctica) and thus a five-continent model as depicted in the Olympic logo.

The terms Oceania
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...

or Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...

are sometimes substituted for Australia to denote a continent encompassing the Australian mainland and various islands of the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 not part of other continents. For example, the Atlas of Canada names Oceania, as does the model taught in Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

, Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

 and in Latin America, Spain and Portugal
Ibero-America
Ibero-America is a term used since the second half of the 19th century to refer collectively to the countries in the Americas that were formerly colonies of Spain or Portugal. Spain and Portugal are themselves included in some definitions, such as that of the Ibero-American Summit and the...

.

Area and population


The following table summarises the area and population of each continent using the seven continent model, sorted by decreasing area.
Continent Area (km²) Area (mi²) Percent of
total landmass
Total population Percent of
total population
Density
People per
km²
Density
People per
mi²
Most populous
city (proper)
Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

43820000 sqkm 29.5% 4,164,252,000 60% 95 /sqkm Shanghai
Shanghai
Shanghai is the largest city by population in China and the largest city proper in the world. It is one of the four province-level municipalities in the People's Republic of China, with a total population of over 23 million as of 2010...

, China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...

Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

30370000 sqkm 20.4% 1,022,234,000 15% 33.7 /sqkm Lagos
Lagos
Lagos is a port and the most populous conurbation in Nigeria. With a population of 7,937,932, it is currently the third most populous city in Africa after Cairo and Kinshasa, and currently estimated to be the second fastest growing city in Africa...

, Nigeria
Nigeria
Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

24490000 sqkm 16.5% 542,056,000 8% 22.1 /sqkm Mexico City
Mexico City
Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...

, Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

17840000 sqkm 12.0% 392,555,000 6% 22 /sqkm São Paulo
São Paulo
São Paulo is the largest city in Brazil, the largest city in the southern hemisphere and South America, and the world's seventh largest city by population. The metropolis is anchor to the São Paulo metropolitan area, ranked as the second-most populous metropolitan area in the Americas and among...

, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

Antarctica 13720000 sqkm 9.2% 1,000 0.00002% 7E-05 /sqkm Villa Las Estrellas
Villa Las Estrellas
Villa Las Estrellas is a Chilean town in Antártica Commune, Antártica Province, Magallanes and Antártica Chilena Region. It is located on President Eduardo Frei Montalva Base, a military base, on King George Island. It is the biggest and one of only two civilian settlements on Antarctica...

, Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

an claim
Antártica
The Chilean Antarctic Territory is the territory in Antarctica claimed by Chile. The Chilean Antarctic Territory ranges from 53°W to 90°W and from the South Pole to 60°S, partially overlapping Argentine and British Antarctic claims...

Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

10180000 sqkm 6.8% 738,199,000 11% 72.5 /sqkm Istanbul
Istanbul
Istanbul , historically known as Byzantium and Constantinople , is the largest city of Turkey. Istanbul metropolitan province had 13.26 million people living in it as of December, 2010, which is 18% of Turkey's population and the 3rd largest metropolitan area in Europe after London and...

, Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

Australia
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

9008500 sqkm 5.9% 29,127,000 0.4% 3.2 /sqkm Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...

, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...



The total land area of all continents is 148647000 sqkm, or 29.1% of earth's surface (510065600 sqkm).

A rough estimate of the total population of all the continents is 7,000,000,000.

Highest and lowest points


The following table lists the seven continents with their highest and lowest points on land, sorted in decreasing highest points.
Continent Highest point Height (m) Height (ft) Country or territory containing highest point Lowest point Depth (m) Depth (ft) Country or territory containing lowest point
Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 
Mount Everest
Mount Everest
Mount Everest is the world's highest mountain, with a peak at above sea level. It is located in the Mahalangur section of the Himalayas. The international boundary runs across the precise summit point...

 
884829,028.9 and Dead Sea
Dead Sea
The Dead Sea , also called the Salt Sea, is a salt lake bordering Jordan to the east and Israel and the West Bank to the west. Its surface and shores are below sea level, the lowest elevation on the Earth's surface. The Dead Sea is deep, the deepest hypersaline lake in the world...

 
-422 m , and '
South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 
Aconcagua
Aconcagua
Aconcagua is the highest mountain in the Americas at . It is located in the Andes mountain range, in the Argentine province of Mendoza and it lies west by north of its capital, the city of Mendoza. The summit is also located about 5 kilometres from San Juan Province and 15 kilometres from the...

 
696022,834.6 Laguna del Carbón
Laguna del Carbón
Laguna del Carbón is an endorheic salt lake in the Gran Bajo de San Julián of Santa Cruz Province, Argentina, 54 km from Puerto San Julián...

 
-105 m
North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 
Mount McKinley
Mount McKinley
Mount McKinley or Denali in Alaska, United States is the highest mountain peak in North America and the United States, with a summit elevation of above sea level. It is the centerpiece of Denali National Park and Preserve.- Geology and features :Mount McKinley is a granitic pluton...

 
619820,334.6 Death Valley
Death Valley
Death Valley is a desert valley located in Eastern California. Situated within the Mojave Desert, it features the lowest, driest, and hottest locations in North America. Badwater, a basin located in Death Valley, is the specific location of the lowest elevation in North America at 282 feet below...

 †
-86 m
Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 
Mount Kilimanjaro
Mount Kilimanjaro
Kilimanjaro, with its three volcanic cones, Kibo, Mawenzi, and Shira, is a dormant volcano in Kilimanjaro National Park, Tanzania and the highest mountain in Africa at above sea level .-Geology:...

 
589519,340.6 Lake Assal  -155 m
Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 
Mount Elbrus
Mount Elbrus
Mount Elbrus is an inactive volcano located in the western Caucasus mountain range, in Kabardino-Balkaria and Karachay-Cherkessia, Russia, near the border of Georgia. Mt. Elbrus's peak is the highest in the Caucasus, in Russia...

 
563318,481 Caspian Sea
Caspian Sea
The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...

 
-28 m and, depending on the Europe-Asia boundary chosen, and/or
Antarctica  Vinson Massif
Vinson Massif
Vinson Massif is the highest mountain of Antarctica, lying in the Sentinel Range of the Ellsworth Mountains, which stand above the Ronne Ice Shelf near the base of the Antarctic Peninsula. The massif is located about from the South Pole and is about long and wide. At the highest point is Mount...

 
489216,049.9 Deep Lake, Vestfold Hills
Vestfold Hills
Vestfold Hills is an area of rounded rock coastal hills, in extent, located at the north side of Sorsdal Glacier on Ingrid Christensen Coast in Antarctica. The hills are subdivided by three west-trending peninsulas bounded by narrow fjords...

 †
-50 m
Australia
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

 
Puncak Jaya
Puncak Jaya
Puncak Jaya or Carstensz Pyramid is the highest summit of Mount Carstensz in the Sudirman Range of the western central highlands of Papua province, Indonesia . Other summits are East Carstensz Peak and Ngga Pulu...

 
488416,023.6 (Papua) Lake Eyre
Lake Eyre
Lake Eyre is the lowest point in Australia, at approximately below sea level, and, on the rare occasions that it fills, it is the largest lake in Australia and 18th largest in the world...

 
-15 m


† 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 Isbræ
Jakobshavn Isbræ
Jakobshavn Isbræ, also known as the Jakobshavn Glacier and Sermeq Kujalleq is a large outlet glacier in West Greenland. It is located near the Greenlandic town of Ilulissat and ends at the sea in the Ilulissat Icefjord....

 (-1512 m) and Bentley Subglacial Trench
Bentley Subglacial Trench
The Bentley Subglacial Trench is a vast topographic trench in Marie Byrd Land, West Antarctica, 80°S, 115°W. At 2,555 meters below sea level, it is the lowest point on the surface of the earth not covered by ocean, although it is covered by ice. Most people do not count it as the lowest point on...

 (-2540 m), but these are covered by kilometers of ice.

Some sources list the Kuma-Manych Depression
Kuma-Manych Depression
The Kuma–Manych Depression , is a geological depression in southwestern Russia that separates the Russian Plain from the Fore-Caucasus...

 (a remnant of the Paratethys
Paratethys
The Paratethys ocean, Paratethys sea or just Paratethys was a large shallow sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in western Asia. The sea was formed during the Oxfordian epoch as an extension of the rift that formed the Central Atlantic Ocean and...

) as the geological border between Europe and Asia. This would place Caucasus outside of Europe, thus making Mont Blanc
Mont Blanc
Mont Blanc or Monte Bianco , meaning "White Mountain", is the highest mountain in the Alps, Western Europe and the European Union. It rises above sea level and is ranked 11th in the world in topographic prominence...

 (elevation 4810 m) in the Graian Alps
Graian Alps
The Graian Alps are a mountain range in the western part of the Alps. They are located in France , Italy , and Switzerland...

 the highest point in Europe - the lowest point would still be the shore of the Caspian Sea.

Other divisions


Aside from the conventionally known continents, the scope and meaning of the term 'continent' may vary. Supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...

s, largely in evidence earlier in the geological record, are landmasses which comprise more than one craton
Craton
A craton is an old and stable part of the continental lithosphere. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by...

 or continental core. These have included Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...

, Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

, Vaalbara
Vaalbara
Vaalbara is theorized to be Earth's first supercontinent, beginning its formation about , completing its formation by about and breaking up by . The name Vaalbara is derived from the South African Kaapvaal craton and the West Australian Pilbara craton...

, Kenorland
Kenorland
Kenorland was one of the earliest supercontinents on Earth. It is believed to have formed during the Neoarchaean Era ~2.7 billion years ago by the accretion of Neoarchaean cratons and the formation of new continental crust...

, Columbia
Columbia (supercontinent)
Columbia, also known as Nuna and Hudsonland, was one of Earth's oldest supercontinents. It was first proposed by J.J.W. Rogers and M. Santosh and is thought to have existed approximately 1.8 to 1.5 billion years ago in the Paleoproterozoic Era. Zhao et al...

, Rodinia
Rodinia
In geology, Rodinia is the name of a supercontinent, a continent which contained most or all of Earth's landmass. According to plate tectonic reconstructions, Rodinia existed between 1.1 billion and 750 million years ago, in the Neoproterozoic era...

, and Pangaea
Pangaea
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....

.

Certain parts of continents are recognized as subcontinent
Subcontinent
A subcontinent is a large, relatively self-contained landmass forming a subdivision of a continent. By dictionary entries, the term subcontinent signifies "having a certain geographical or political independence" from the rest of the continent, or "a vast and more or less self-contained subdivision...

s, particularly those on different tectonic plates
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

 to the rest of the continent. The most notable examples are the Indian subcontinent
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...

 and the Arabian Peninsula
Arabian Peninsula
The Arabian Peninsula is a land mass situated north-east of Africa. Also known as Arabia or the Arabian subcontinent, it is the world's largest peninsula and covers 3,237,500 km2...

. Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

, generally reckoned as the world's largest island on the northeastern periphery of the North American Plate
North American Plate
The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

, is sometimes referred to as a subcontinent. Where the Americas are viewed as a single continent (America), it is divided into two subcontinents (North America and South America) or various regions.

Some areas of continental crust
Continental crust
The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to more felsic, or granitic, bulk composition, which lies in...

 are largely covered by the sea and may be considered submerged continent
Submerged continent
A submerged continent is a continental mass, extensive in size, but mainly undersea. The terminology is used by some paleogeologists and geographers in reference to some land masses.The two main examples in this class are the Kerguelen Plateau and Zealandia...

s. Notable examples are Zealandia
Zealandia (continent)
Zealandia , also known as Tasmantis or the New Zealand continent, is a nearly submerged continental fragment that sank after breaking away from Australia 60–85 million years ago, having separated from Antarctica between 85 and 130 million years ago...

, emerging from the sea primarily in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 and New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...

, and the almost completely submerged Kerguelen continent
Kerguelen Plateau
The Kerguelen Plateau is an underwater volcanic large igneous province , also the microcontinent and submerged continent in the southern Indian Ocean. It lies about 3,000 km to the southwest of Australia and is nearly three times the size of Japan...

 in the southern Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

.

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 microcontinents
Continental fragment
Continental crustal fragments, partially synonymous with microcontinents, are fragments of continents thought to have been broken off from the main continental mass forming distinct islands, possibly several hundred kilometers from their place of origin...

. Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

, the largest example, is usually considered an island of Africa but has been referred to as "the eighth continent" from a biological perspective.

Early concepts of the Old World continents




The first distinction between continents was made by ancient Greek
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

 mariners who gave the names Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 to the lands on either side of the waterways of the Aegean Sea
Aegean Sea
The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...

, the Dardanelles
Dardanelles
The Dardanelles , formerly known as the Hellespont, is a narrow strait in northwestern Turkey connecting the Aegean Sea to the Sea of Marmara. It is one of the Turkish Straits, along with its counterpart the Bosphorus. It is located at approximately...

 strait, the Sea of Marmara
Sea of Marmara
The Sea of Marmara , also known as the Sea of Marmora or the Marmara Sea, and in the context of classical antiquity as the Propontis , is the inland sea that connects the Black Sea to the Aegean Sea, thus separating Turkey's Asian and European parts. The Bosphorus strait connects it to the Black...

, the Bosporus
Bosporus
The Bosphorus or Bosporus , also known as the Istanbul Strait , is a strait that forms part of the boundary between Europe and Asia. It is one of the Turkish Straits, along with the Dardanelles...

 strait and the Black Sea
Black Sea
The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...

. The names were first applied just to lands near the coast and only later extended to include the hinterlands. 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 ..."

Ancient Greek thinkers subsequently debated whether Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 (then called Libya) should be considered part of Asia or a third part of the world. Division into three parts eventually came to predominate. From the Greek viewpoint, the Aegean Sea was the center of the world; Asia lay to the east, Europe to the west and north and Africa to the south. 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
Rioni River
The Rioni or Rion River is the main river of western Georgia. It originates in the Caucasus Mountains, in the region of Racha and flows west to the Black Sea, entering it north of the city of Poti...

 (known then as the Phasis) in Georgia
Georgia (country)
Georgia is a sovereign state in the Caucasus region of Eurasia. Located at the crossroads of Western Asia and Eastern Europe, it is bounded to the west by the Black Sea, to the north by Russia, to the southwest by Turkey, to the south by Armenia, and to the southeast by Azerbaijan. The capital of...

. Later it was viewed as running from the Black Sea through Kerch Strait, the Sea of Azov
Sea of Azov
The Sea of Azov , known in Classical Antiquity as Lake Maeotis, is a sea on the south of Eastern Europe. It is linked by the narrow Strait of Kerch to the Black Sea to the south and is bounded on the north by Ukraine mainland, on the east by Russia, and on the west by the Ukraine's Crimean...

 and along the Don River (known then as the Tanais) in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. The boundary between Asia and Africa was generally taken to be the Nile
Nile
The Nile is a major north-flowing river in North Africa, generally regarded as the longest river in the world. It is long. It runs through the ten countries of Sudan, South Sudan, Burundi, Rwanda, Democratic Republic of the Congo, Tanzania, Kenya, Ethiopia, Uganda and Egypt.The Nile has two major...

 River. Herodotus
Herodotus
Herodotus was an ancient Greek historian who was born in Halicarnassus, Caria and lived in the 5th century BC . He has been called the "Father of History", and was the first historian known to collect his materials systematically, test their accuracy to a certain extent and arrange them in a...

 in the 5th century BC, however, objected to the unity of Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

 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, a debate that continues nearly two and a half millennia later.

Eratosthenes
Eratosthenes
Eratosthenes of Cyrene was a Greek mathematician, poet, athlete, geographer, astronomer, and music theorist.He was the first person to use the word "geography" and invented the discipline of geography as we understand it...

, 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
Isthmus
An isthmus is a narrow strip of land connecting two larger land areas usually with waterforms on either side.Canals are often built through isthmuses where they may be particularly advantageous to create a shortcut for marine transportation...

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
Caspian Sea
The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...

, and the border between Asia and Africa at the isthmus between the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...

 and the mouth of Lake Bardawil
Lake Bardawil
Lake Bardawil is a large, very saline lake in Egypt on the north coast of the Sinai Peninsula. The lagoon is shallow and is separated from the Mediterranean Sea by a narrow sandbar. It has Ramsar Convention protected wetlands.Lake Bardawil is about long, and wide...

 on the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

.

Through the Roman period and the Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

, a few writers took the Isthmus of Suez
Isthmus of Suez
The Isthmus of Suez is the narrow strip land that lies between the Mediterranean Sea and the Red Sea, linking the continents of Africa and Asia. It contains the country of Egypt and the Suez Canal. Like many isthmuses, it is a location of great strategic value....

 as the boundary between Asia and Africa, but most writers continued to take it to be the Nile or the western border of Egypt (Gibbon). In the Middle Ages the world was usually portrayed on T and O map
T and O map
A T and O map or O-T or T-O map , is a type of medieval world map, sometimes also called a Beatine map or a Beatus map because one of the earliest known representations of this sort is attributed to Beatus of Liébana, an 8th-century Spanish monk...

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
Libya
Libya is an African country in the Maghreb region of North Africa bordered by the Mediterranean Sea to the north, Egypt to the east, Sudan to the southeast, Chad and Niger to the south, and Algeria and Tunisia to the west....

] farther west, had even then scarcely passed away".

European arrival in the Americas


Christopher Columbus
Christopher Columbus
Christopher Columbus was an explorer, colonizer, and navigator, born in the Republic of Genoa, in northwestern Italy. Under the auspices of the Catholic Monarchs of Spain, he completed four voyages across the Atlantic Ocean that led to general European awareness of the American continents in the...

 sailed across the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 to the West Indies
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

 in 1492, sparking a period of European exploration of the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

. 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
Amerigo Vespucci
Amerigo Vespucci was an Italian explorer, financier, navigator and cartographer. The Americas are generally believed to have derived their name from the feminized Latin version of his first name.-Expeditions:...

 and Gonçalo Coelho
Gonçalo Coelho
Gonçalo Coelho was a Portuguese explorer who belonged to a prominent family in northern Portugal. He commanded two expeditions which explored much of the coast of Brazil....

 attempted to sail around what they considered to be the southern end of the Asian mainland into the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

, passing through the Matsackson Islands. After reaching the coast of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, they sailed a long way further south along the coast of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, confirming that this was a land of continental proportions and that it also extended much further south than Asia was known to. On return to Europe, an account of the voyage, called Mundus Novus ("New World"), was published under Vespucci’s name in 1502 or 1503, although it seems that it had additions or alterations by another writer. Regardless of who penned the words, Mundus Novus attributed 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", 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
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 connected to Asia and showed South America as a separate land.

In 1507 Martin Waldseemüller
Martin Waldseemüller
Martin Waldseemüller was a German cartographer...

 published a world map, Universalis Cosmographia
Waldseemüller map
The Waldseemüller map, Universalis Cosmographia, is a printed wall map of the world by German cartographer Martin Waldseemüller, originally published in April 1507. It is known as the first map to use the name "America". The map is drafted on a modification of Ptolemy's second projection, expanded...

, 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
Cosmographiae Introductio
Cosmographiae Introductio was a book published in 1507 to accompany Martin Waldseemüller's printed globe and wall-map , which were the first appearance of the name 'America'...

, 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. 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 and translated from the Latin terra continens. The noun was used to mean "a connected or continuous tract of land" or mainland
Mainland
Mainland is a name given to a large landmass in a region , or to the largest of a group of islands in an archipelago. Sometimes its residents are called "Mainlanders"...

. 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
Isle of Man
The Isle of Man , otherwise known simply as Mann , is a self-governing British Crown Dependency, located in the Irish Sea between the islands of Great Britain and Ireland, within the British Isles. The head of state is Queen Elizabeth II, who holds the title of Lord of Mann. The Lord of Mann is...

, Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 and Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

 and in 1745 to Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

. 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.

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
Peter Heylin
Peter Heylin or Heylyn was an English ecclesiastic and author of many polemical, historical, political and theological tracts. He incorporated his political concepts into his geographical books Microcosmus in 1621 and Cosmographie .-Life:He was born in Burford, Oxfordshire, the son of Henry Heylyn...

 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
Ephraim Chambers
Ephraim Chambers was an English writer and encyclopaedist, who is primarily known for producing the Cyclopaedia, or a Universal Dictionary of Arts and Sciences.-Early life:...

 wrote in his Cyclopædia, "The world is ordinarily divided into two grand continents: the old
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....

 and the new
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...

." And in his 1752 atlas, Emanuel Bowen
Emanuel Bowen
Emanuel Bowen was an English map engraver, who worked for George II of England and Louis XV of France as a geographerHe published a 'Complete Atlas of Geography,' 1744-7; an 'English Atlas, with a new set of maps,' 1745; a 'Complete Atlas .....

 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." However, the old idea of Europe, Asia and Africa as "parts" of the world ultimately persisted with these being regarded as separate continents.

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.

Europeans discovered Australia
Australia (continent)
Australia is the world's smallest continent, comprising the mainland of Australia and proximate islands including Tasmania, New Guinea, the Aru Islands and Raja Ampat Islands...

 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). In 1813 Samuel Butler
Samuel Butler (schoolmaster)
Samuel Butler FRS was an English classical scholar and schoolmaster of Shrewsbury, and Bishop of Lichfield. His grandson was Samuel Butler , noted author of the novel "Erewhon"....

 wrote of Australia as "New Holland
New Holland (Australia)
New Holland is a historic name for the island continent of Australia. The name was first applied to Australia in 1644 by the Dutch seafarer Abel Tasman as Nova Hollandia, naming it after the Dutch province of Holland, and remained in use for 180 years....

, an immense island, which some geographers dignify with the appellation of another continent" and the Oxford English Dictionary
Oxford English Dictionary
The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

was just as equivocal some decades later.

Antarctica was sighted in 1820 and described as a continent by Charles Wilkes
Charles Wilkes
Charles Wilkes was an American naval officer and explorer. He led the United States Exploring Expedition, 1838-1842 and commanded the ship in the Trent Affair during the American Civil War...

 on the United States Exploring Expedition
United States Exploring Expedition
The United States Exploring Expedition was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States from 1838 to 1842. The original appointed commanding officer was Commodore Thomas ap Catesby Jones. The voyage was authorized by Congress in...

 in 1838, the last continent to be 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
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

.

From the mid-19th century, United States atlases 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 United States atlases to treat them as one continent up until World War II. The Olympic flag
Olympic symbols
The Olympic symbols are icons, flags and symbols used by the International Olympic Committee to promote the Olympic Games. Some—such as the flame, fanfare, and theme—are more common during Olympic competition, but others, such as the flag, can be seen throughout the year.-Motto:The Olympic motto is...

, devised in 1913, has five rings representing the five inhabited, participating continents, with America being treated as one continent and Antarctica not included.

From the 1950s, most United States geographers divided America in two—consistent with modern understanding of geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 and plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

. With the addition of Antarctica, this made the seven-continent model. However, this division of America never appealed to Latin America
Latin America
Latin America is a region of the Americas where Romance languages  – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...

, which saw itself spanning an America that was a single landmass, and there the conception of six continents remains, as it does in scattered other countries.

In recent years there has been a push for Europe and Asia together to be considered a single continent, dubbed "Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

". In this model, the world is divided into six continents (if North America and South America are considered separate continents).

Geology


Geologists use the term continent in a different manner from geographers, where a continent is defined by continental crust
Continental crust
The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to more felsic, or granitic, bulk composition, which lies in...

: a platform of metamorphic
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...

 and igneous rock
Igneous rock
Igneous rock is one of the three main rock types, the others being sedimentary and metamorphic rock. Igneous rock is formed through the cooling and solidification of magma or lava...

, largely of granitic
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 composition. Some geologists restrict the term 'continent' to portions of the crust built around stable Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...

 "shield", typically 1.5 to 3.8 billion years old, called a craton
Craton
A craton is an old and stable part of the continental lithosphere. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by...

. The craton itself is an accretionary
Accretion (geology)
Accretion is a process by which material is added to a tectonic plate or a landmass. This material may be sediment, volcanic arcs, seamounts or other igneous features.-Description:...

 complex of ancient mobile belts (mountain belts) from earlier cycles of subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...

, continental collision
Continental collision
Continental collision is a phenomenon of the plate tectonics of Earth that occurs at convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains produced, and two continents sutured together...

 and break-up from plate tectonic
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

 activity. An outward-thickening veneer of younger, minimally deformed sedimentary rock
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....

 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 deltaic
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...

 sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

s. Beyond the margin, there is either a continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

 and drop off to the basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

ic ocean basin
Oceanic basin
Hydrologically, an oceanic basin may be anywhere on Earth that is covered by seawater, but geologically ocean basins are large geologic basins that are below sea level...

 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" compared to much of geologic history.
Some argue that continents are accretionary crustal
Continental crust
The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to more felsic, or granitic, bulk composition, which lies in...

 "rafts" which, 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
East European craton
The East European craton is the core of the Baltica proto-plate and consists of three crustal regions/segments: Fennoscandia to the northwest, Volgo-Uralia to the east, and Sarmatia to the south...

 and Indian craton). Younger mobile belts (such as the Ural Mountains
Ural Mountains
The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...

 and Himalayas
Himalayas
The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...

) mark the boundaries between these regions and the rest of Eurasia.

There are many microcontinents that are built of continental crust but do not contain a craton. Some of these are fragments of Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

 or other ancient cratonic continents: Zealandia
Zealandia (continent)
Zealandia , also known as Tasmantis or the New Zealand continent, is a nearly submerged continental fragment that sank after breaking away from Australia 60–85 million years ago, having separated from Antarctica between 85 and 130 million years ago...

, which includes New Zealand
Geography of New Zealand
The geography of New Zealand encompasses two main islands and a number of smaller islands, located near the centre of the water hemisphere. New Zealand varies in climate, from cold and wet to dry and to subtropical in some areas...

 and New Caledonia
Geography of New Caledonia
The geography of New Caledonia , an overseas collectivity of France located in the subregion of Melanesia, makes the continental island group unique in the southwest Pacific. Among other things, the island chain has played a role in preserving unique biological lineages from the Mesozoic...

; Madagascar
Geography of Madagascar
Madagascar is an island in the Indian Ocean off the eastern coast of southern Africa, east of Mozambique. It is the fourth largest island in the world. The highest point is Maromokotro, in the Tsaratanana Massif region in the north of the island, at . The capital Antananarivo is in the Hauts...

; the northern Mascarene Plateau
Mascarene Plateau
The Mascarene Plateau is an submarine plateau in the Indian Ocean, north and east of Madagascar. The plateau extends approximately 2000 km, from the Seychelles in the north to Réunion in the south. The plateau covers an area of over 115,000 km² of shallow water, with depths ranging from...

, which includes the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....

. Other islands, such as several in the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....

, 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
Kerguelen Plateau
The Kerguelen Plateau is an underwater volcanic large igneous province , also the microcontinent and submerged continent in the southern Indian Ocean. It lies about 3,000 km to the southwest of Australia and is nearly three times the size of Japan...

, for example, is largely volcanic, but is associated with the breakup of Gondwanaland and is considered to be a microcontinent, whereas volcanic Iceland
Geography of Iceland
Iceland is a medium-sized island in the North Atlantic ocean. The island is located east of Greenland and immediately south of the Arctic Circle, atop the divergent boundary of the Mid-Atlantic Ridge in the North Atlantic Ocean. It lies about from New York City and from Scotland...

 and Hawaii
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...

 are not. The British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

, Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...

, Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

, and Newfoundland are margins of the Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...

n continent which are only separated by inland seas flooding its margins.

Plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

 offers yet another way of defining continents. Today, Europe and most of Asia comprise the unified Eurasian Plate
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...

 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
Isthmus
An isthmus is a narrow strip of land connecting two larger land areas usually with waterforms on either side.Canals are often built through isthmuses where they may be particularly advantageous to create a shortcut for marine transportation...

 being largely the result of volcanism
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 from relatively recent subduction tectonics. North American continental rocks extend to Greenland (a portion of the Canadian Shield
Canadian Shield
The Canadian Shield, also called the Laurentian Plateau, or Bouclier Canadien , is a vast geological shield covered by a thin layer of soil that forms the nucleus of the North American or Laurentia craton. It is an area mostly composed of igneous rock which relates to its long volcanic history...

), 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
Columbia (supercontinent)
Columbia, also known as Nuna and Hudsonland, was one of Earth's oldest supercontinents. It was first proposed by J.J.W. Rogers and M. Santosh and is thought to have existed approximately 1.8 to 1.5 billion years ago in the Paleoproterozoic Era. Zhao et al...

 or Nuna formed during a period of 2.0–1.8 billion years and broke up about 1.5–1.3 billion years ago. The supercontinent Rodinia
Rodinia
In geology, Rodinia is the name of a supercontinent, a continent which contained most or all of Earth's landmass. According to plate tectonic reconstructions, Rodinia existed between 1.1 billion and 750 million years ago, in the Neoproterozoic era...

 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
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....

; Pangaea broke up into Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...

 (which became North America and Eurasia) and Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

 (which became the remaining continents).

See also




  • List of sovereign states and dependent territories by continent
  • List of supercontinents
  • Subregion
    Subregion
    A subregion is a conceptual unit which derives from a larger region or continent and is usually based on location. Cardinal directions, such as south or southern, are commonly used to define a subregion.- United Nations subregions :...



External links