Location: Articles
Where Did That Island Come From Anyway?
Islands are unique ecosystems steeped in mystery, adventure and novelty. The isolation of islands effects the types of plants and animals found on them. Ninety five percent of Hawaii's plants are found nowhere else in the world. How islands are formed is equally unique. Geologically speaking, not all islands are created equally. Geographers claim two major classifications of islands: oceanic islands and continental islands.
Oceanic islands exist in the open sea and are not attached to any continental mass. These islands are a result of two processes, volcanic activity or coral deposits. Most of the oceanic islands originated from ancient volcanic activity. Volcanic islands occur along the boundaries of tectonic plates, sections of the Earth’s crust that collide and move apart, often causing land to rise above sea level. Evidence of this process can be seen in the “island arcs” of Japan and the Philippines.
Volcanic islands are also created by “hot spots”. From deep within the earth's mantle, magma rises up and spews lava onto the sea floor. Over time, all of this lava buildup emerges above sea level to form an island volcano. The movement of a tectonic plate eventually carries the island beyond the hotspot, cutting it off from the magma source. The island volcano then becomes extinct, but another one develops over the hotspot and the cycle repeats, creating even more volcanic islands. Over millions of years, these hotspots have left a trail of famous islands like Hawaii, the Canary Islands and the island nation of Tuvalu.
The second type of oceanic island is a coral island. These islands are formed by coral building sea organisms known as polyps. Polyps protect their bodies by building limestone walls around themselves. Over time, these colonies grow large enough to form reefs. Through a process that takes millions of years, these reefs become so expansive that they can cover hundreds of square kilometers. Reefs form the basis for islands. An island is formed if the sea level drops around the reef, or land on which the reef rests, rises, causing the submerged reef to be exposed. Over time, sand and dust accumulate on the reef, eventually forming an island. Although not as numerous as volcanic islands, well-known coral islands are found in the Florida Keys, Zanzibar and the Bahamas.
The second type of oceanic island is a coral island. These islands are formed by coral building sea organisms known as polyps. Polyps protect their bodies by building limestone walls around themselves. Over time, these colonies grow large enough to form reefs. Through a process that takes millions of years, these reefs become so expansive that they can cover hundreds of square kilometers. Reefs form the basis for islands. An island is formed if the sea level drops around the reef, or land on which the reef rests, rises, causing the submerged reef to be exposed. Over time, sand and dust accumulate on the reef, eventually forming an island. Although not as numerous as volcanic islands, well-known coral islands are found in the Florida Keys, Zanzibar and the Bahamas.
Continental islands form the second island subgroup. Continental islands are bodies of land connected to a continent. These islands tend to sit in shallow waters, existing in 600 feet of water or less. There are a number of ways that these islands can come into existence. Often, continental islands are created by a rise in sea level where only the highest points of the land remain above water. This is exactly how much of present day New York City was created – after all, Manhattan is an island. Similarly, a continental island may be formed when water breaks or cuts through a peninsula, separating it from the mainland. Malaysia is renowned for its stunning peninsular islands.
Unique subgroups of continental islands existing throughout the world are known as microcontinental islands. Microcontinental islands are formed when a portion of the landmass separates from the continent; island nations such as Madagascar and Cuba are good examples.
And just in case anyone thought islands were a finite resource, artificial islands are becoming more common in recent times. But artificial islands are not just a creation of modern civilization. For thousands of years, humans have been building their own islands. The ancient Aztecs built their capital Tenochtitlan (present day Mexico City) on an ancient lake. Other notable artificial islands include Île Notre-Dame in Canada and “The Pearl” in Qatar.
And just in case anyone thought islands were a finite resource, artificial islands are becoming more common in recent times. But artificial islands are not just a creation of modern civilization. For thousands of years, humans have been building their own islands. The ancient Aztecs built their capital Tenochtitlan (present day Mexico City) on an ancient lake. Other notable artificial islands include Île Notre-Dame in Canada and “The Pearl” in Qatar.
Building artificial islands is actually easier than it looks. To create an artificial island these days, contractors typically dump large volumes of dredge sediment, rocks, cement, soil or even trash into the water, thus forming a base on which development can occur.
Despite this simple process, humans have recently taken the process to a whole new level, and are truly beginning to shape the face of the Earth. The leader in ultra modern artificial island development appears to be Dubai, UAE. With the construction of the “The Palm Islands” and the soon to be completed “The World Islands,” engineers are building some the most ambitious artificial island projects in history.
Although not all islands are created equally, all are equally unique. Every naturally formed island is the result of millions of years of geological artistry. Every artificial island is the result of humanity's ambition to create a perfect island paradise.
http://www.privateislandsonline.com
Rate:
Add Feedback
PrintRelated Content
 Clear Water off Bali's Distant Deer Island
Rate:
|
 an Article by Bob Payne
Rate:
|
 On this Indonesian island, the hills are alive with the music of gamelan - By Mary Roach
Rate:
|
Rate:
|
