Archipelago

An archipelago, also called an island group or island chain, is a cluster or collection of islands found in an ocean, sea or smaller body of water. Indonesia, whose territory comprises most of the Indonesian Archipelago, is the largest archipelago nation in the world. Archipelagos form through more than one process: oceanic islands typically rise from the seafloor through volcanic activity and have no underlying continental rock, while continental-fragment archipelagos are pieces of a continent separated by processes such as glacial cutting, and coral-cay archipelagos build up where ocean currents deposit sediment on existing coral reefs. This entity is placed among the atlas volcanic formations because volcanic activity produces the classic oceanic island chain, though the type also covers the non-volcanic origins the lead describes.