Have you ever seen islands spread across a water body, thousands in number? What a sight! Known as “Archipelago”, the chain of islands share a common source and were formed millions of years ago.
Hot spots
Archipelago is the result of an underwater volcanic activity in the ocean. The Hawaiian Islands are an example.
Beneath the earth’s surface is a ‘hot spot’ (very hot region) that releases magma or semi molten rock. This forms rock-like structures underwater. As magma continues to flow, over a period of time these structures rise up out of water. This forms an island. While the single hot spot remains, the persistent plate movements on the earth’s surface shift the magma, and a series of islands is formed in one area.
Some islands have inactive volcanoes. Others like the Hawaiian Islands and many regions in the Japanese Archipelago experience active volcanoes. Four big islands and more than 3,000 small ones make up the Japanese Archipelago.
Taking shape
However, not all archipelagos are volcanic in origin. As a result of global warming, glaciers melt, causing the sea level to rise and the valleys to flood. Existing islands disappear, and a series of islands appear. The Malay Archipelago, the world’s largest archipelago, falls between the Pacific and the Indian Ocean and has 25,000 islands which were originally part of the Asian landmass. When the glaciers melted, these islands emerged. Indonesia and Malaysia have numerous islands that belong to this archipelago.
The Archipelago Sea and the islands in Finland have a different origin. The land on which the glaciers stood crumpled because of the weight. As the glaciers melted, this land regained its shape with more than 50,000 islands (many of them tiny) in number. The islands continue to form and are connected by bridges.
Why do archipelagos have distinct landscape? The reason is the constant shifting of the earth’s plates. From stony beaches to waterfalls to mountainous terrains and volcanic emission, one can see it all. Archipelagos also vary in size. Indonesia, part of the world’s largest archipelago has bigger islands compared to Hawaii where tiny islands neighbour a core island.
More than one
Countries such as Indonesia, New Zealand, Philippines, United Kingdom and Japan are archipelagos.
Canadian Arctic Archipelago has more than 36,000 islands and most of them unoccupied.
Indonesian Archipelago is made up of approximately 17,500 islands out of which more than 6,000 are populated. It has 60 tiny archipelagos and five core islands.Out of 400, about 150 are active volcanoes.
