Archipelago (Meaning and Explanation)

We explain what an archipelago is, how the islands that make it up are formed, their types and examples from various parts of the world.

What is an archipelago?

In geography, an archipelago is called a group of islands grouped in a relatively small maritime portion that is, not too distant from each other, although they are usually very numerous. In addition to islands themselves, archipelagos may also have other types of islets, cays and reefs.

The term archipelago comes from the Greek arch (“upper”) and pelagos (“sea”). It was the term used in classical antiquity to refer to the Aegean Sea (“upper sea” or “main sea”), given that it was full of islands. In later times it came to be used to call the islands of the Aegean Sea, and by extension, the groups of islands that resembled them.

Archipelagos are numerous in the world, although the majority are concentrated in Southeast Asia and between the northeast coast of the United States and Greenland.

Why are islands formed?

The islands are the product of different geological processes, that is, the changes that the Earth's crust undergoes over time. Just as continents form, islands of different types also form. In that sense, we can talk about:

continental islands which have the same origin as the rest of the continent, and in fact are connected to it by the continental shelf, although they are separated on the surface by a shallow mass of water (no more than 200 meters deep). Many of them were part of the continent itself in times past when the ocean water level was lower.
volcanic islands which are the result of the action of underwater volcanoes, that is, the deposition of underground materials on the surface, where they cool and become solid soil. They are the most recent type of islands of all.
mixed islands in which seismic or volcanic action is combined with the continental plate itself, giving rise to a combination of the two previous cases.
coral islands usually flat and low, formed due to the accumulation of coral material on a shallow underwater platform, usually of a volcanic type.
sedimentary islands that is, the result of the accumulation of sediments, generally at the mouth of large rivers that carry significant amounts of sand, gravel, mud and other materials, which over time become compacted and solidify. They generally form a delta at the mouth of the river.
river islands which are formed in the middle of rivers due to changes in their course or channel, which allow the emergence of solid crests, shoals or floodable swampy depressions.

Types of archipelagos

Similarly, archipelagos are classified according to their geological origin, but in this case only two categories are differentiated:

Oceanic archipelagos made up of islands generally of volcanic origin, and which are not part of any continental plate.
continental archipelagos made up of continental islands, that is, islands that are part of a continental plate, although they are separated from it by shallow areas of water.

Examples of archipelagos

galapagos archipelago ecuador — The Galapagos Islands are home to the second most important marine reserve in the world.

Examples of archipelagos in different parts of the world are the following:

The Hawaiian archipelago located in the North Pacific and belonging to the United States, is made up of nine islands and atolls, the largest of which is, precisely, Hawaii Island. It is the most isolated archipelago on the planet.
The Galapagos Islands belonging to Ecuador and located 1000 km from its coasts, in the Pacific Ocean. It is made up of thirteen islands of volcanic origin and another 107 small islets, where the second most important marine reserve on the planet is located, declared a world heritage site by UNESCO in 1978.
The Canary Islands archipelago located on the northwest African coast and politically belonging to Spain, is made up of eight islands, five islets and eight rocks. It is a set of volcanic islands that sit on the African continental plate, and are part of the natural region of Macaronesia.
The Chiloé archipelago located in the south of Chile, is made up of a large island (Isla Grande de Chiloé) and a significant number of smaller islands, distributed in groups of three and four around the largest. This archipelago corresponds to the foothills of the Chilean Coastal mountain range, submerged except for its peaks.
The Los Roques archipelago belonging to Venezuela and located 176 km from its capital city, in the Atlantic Ocean, and is where the largest coral reef in the Caribbean Sea is located. It has an unusual atoll shape, more common in the Pacific Ocean, and includes about 42 cays with an internal lagoon and 1,500 km of coral reefs.
The Malay Archipelago also called Insulindia, is the island region of Southeast Asia, located between the Indian and Pacific oceans, and covering all or part of the territory of seven countries: Brunei, the Philippines, Indonesia, Malaysia, Papua New Guinea, Singapore and East Timor. There are more than 25,000 different islands, grouped into three groups: the Sunda Islands, the Moluccas Islands and the Philippine Islands.