Island

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ISLAND

An island is a body of land which is surrounded by water; typically a lake, river, or ocean. Islands can be small or large and there are six major kinds of islands. According to National Geographic, these six types are continental, tidal, barrier, oceanic, coral, and artificial:

Continental Islands were attached to a continent at some point. An example of this would be any of the 7 continents (Africa, Antarctica, Australia, Europe, North America, and South America) as they were all supposedly attached millions of years ago via the super-continent named Pangaea. Islands in the Mississippi such as Bay Island, Cottonwood Island, and Sand Bar Island are continental island which were formed by river erosion.

Tidal Islands "are a type of continental island where land connecting the island to the mainland has not completely eroded but is underwater at high tide" (2012). Two examples of tidal islands are Mont Saint-Michel in Normandy, France and the Holy Island of Lindisfarne in Northumberland, United Kingdom.

Barrier Islands are skinny islands which board coastlines. They typically are part of continental island and are made of "sediment-sand, silt, and gravel" (2012). They are "separated from [the] shore by a lagoon or a sound" and are called barrier islands because they "act as barriers between the ocean and the mainland" (2012). An example of a barrier island is Petit Bois Island in the Mississippi Gulf Goast, which is home of six barrier islands.

Oceanic Islands are islands which have been formed by eruptions of volcanoes. As volcanoes erupt, "they build up layers of lava that may eventually break the water's surface" (2012). The tops of the volcanoes then appear above the water which forms an island. Examples of oceanic islands are Hawaii in the United States and Bora Bora in French Polynesia.

Coral Islands are formed in warmer waters by tiny sea animals. These animals are called corals, which "build up hard external skeletons of calcium carbonate" or limestone (2012). Colonies of corals form huge reefs which thicken against seafloors and eventually poke out among the water's surface. Examples of coral islands include the Bahamas in the Atlantic Ocean and Caribbean Sea as well as St. Martin in Bangladesh.

Artificial Islands are islands which are man-made. These islands can be made by water being drained around it or due to material brought in from other places. Examples of artificial islands are Palm Jumeirah and The World Islands which are both located in Dubai in the United Arab Emirates.

SOURCES:
Evers, J. (Ed.). (2012, October 09). Island. Retrieved July 07, 2019, from https://www.nationalgeographic.org/encyclopedia/island/

Great Rivers Ecology
updated 07/2019 by angtcm