As islands are formed

As islands are formed

In the world there is a set of islands. Some were formed several millions years ago, and others exist only several decades. All features of flora and fauna of islands often depend on a way of formation of this territory.

There are three types of islands: continental, volcanic and coral. Formation of islands happened not only many thousands years ago, but also now there are new island territories.

How continental islands were formed?

Continental islands were formed because of the movement of tectonic plates of earth crust. Once islands were a part of big continents. Vertical movements of tectonic plates together with a raising of global sea level formed breaks in continents. The nature of continental islands and the nature of the next to them of the continent are almost identical. Continental or continental islands are located within the uniform shelf, or divided with the continent a deep break. Greenland, Novaya Zemlya, Madagascar, the British Isles, etc. treat continental islands.

How volcanic islands are formed?

In oceans constantly there is a volcanic activity. The throwing-up volcano marks out a huge number of a lava which, stiffening at contact with water and air, forms new volcanic islands. Such islands test a big water erosion and gradually leave under water. Volcanic islands often are considerably removed from continents and form a unique ecological system. The chain of the Hawaiian Islands can be an example of volcanic islands.

How coral islands are formed?

Such islands are capable to be formed only in the equatorial and tropic latitudes. Shallows become populated by corals and polyps which are hooked by roots for a seabed. Over time the lower part of corals hardens, forming strong foundation of the island. Such basis begins to detain sand which the ocean bears the current. Coral reeves which become populated by the most exotic animals of the ocean are formed. An excellent example of such islands is the Great Barrier Reef near coast of Australia.

Author: «MirrorInfo» Dream Team