- Continental crust: definition and origin
- Continental models
- The traditional view
- Special cases
- References
The continental surface is a large, continuous, and discrete landmass, ideally separated by water. Geologically, the continental surface is not defined by its size or location, but by the rocks that compose it and the origin of said matter.
There are some cases like Asia, Europe and Africa, which are not separated by the oceans. The same is the case with North and South America. In fact, if you combine those land masses, you only get four continents.
Continental crust: definition and origin
The number of continents has changed throughout the evolution of the Earth. Plate tectonics and continental drift have forced changes in the continental composition.
The planet began with a single land mass (in the Mesozoic Era). This continent did not appear there suddenly; it was the result of the partial solidification of magma that was crumbled by plate tectonics and continental drift. Those forces continue to function today.
Continental models
The seven continents model is generally taught in China and most English-speaking countries.
A six continent model combining Europe and Asia is preferred by the former parts of the USSR and Japan. And another six-continent model combining North and South America is taught in Latin America and most of Europe.
The answer to what a continent is has to do more with conventions than with a strict definition.
The traditional view
Most people begin geography lessons by learning that there are seven continents in the world.
These have traditionally been listed as Asia, Europe, Africa, Australia, North America, South America, and Antarctica.
However, some have also grown up learning that there are six continents, where Europe and Asia meet as one continent: Eurasia.
Less frequently, some classifications have merged North and South America, generating the Americas.
When geographers identify a continent, they generally include all the islands associated with it.
For example, Japan is part of the Asian continent. Greenland and all the islands in the Caribbean Sea are generally considered part of North America.
Together, the continents total about 148 million square kilometers (57 million square miles) of land.
Special cases
The continents make up most of the planet's land surface, but not all of it.
A very small part of the total land area is made up of islands that are not considered physical parts of the continents.
New Zealand, French Polynesia, and the Hawaiian Islands are examples of land areas that are considered micro-continents.
These areas are generally grouped with culturally similar continents, but are geologically different.
References
- Coffey, J. (nd). Universe Today. Retrieved from universetoday.com
- National Geographic. (sf). Retrieved from nationalgeographic.org
- Spencer, C. (nd). Study.com. Retrieved from study.com
- Worldatlas. (sf). Retrieved from worldatlas.com