Islands of the Atlantic Ocean
The Atlantic Ocean is the Earth's second largest ocean, covering an area in the region of 106 million km² — approximately one-fifth of its surface. The ocean forms an S-shaped basin separating the Americas, on the west, from the landmasses of Eurasia and Africa, on the east.
Important marginal and regional seas include the Adriatic Sea, the Aegean Sea, the Alboran Sea, the Sea of Azov, the Baltic Sea, the Black Sea, the Celtic Sea, the Gulf of Finland, the Ionian Sea, the Kattegat, the Ligurian Sea, the North Sea, the Gulf of Riga, and the Tyrrhenian Sea. Without its marginal seas the Atlantic covers and area of some 82 million km².
The islands of the Atlantic Ocean are concentrated primarily along the continental coasts and within the great marginal seas of the North Atlantic.
The Caribbean region includes the Greater Antilles and Lesser Antilles, where some of the Atlantic's largest islands, such as Hispaniola (73,929 km²) and Cuba (105,806 km²), are found. Comprising Cuba, Jamaica, Hispaniola, Puerto Rico and numerous offshore islands and islets the Greater Antilles are of continental origin. On the northern side of the Greater Antilles are found the great carbonate banks that give rise to the Bahamas and the Turks & Caicos Islands. The Lesser Antilles (comprising the Leeward Islands, Windward Islands, and the Leeward Antilles) are generally smaller islands of volcanic and sedimentary origin. They form a curve extending east from the Greater Antilles, trending south before stretching back to the west off the northern coast of South America.
A second great marginal sea is the almost enclosed basin of the Mediterannean Sea. At 2.5 million km² in area the Mediterannean contains numerous large islands such as Sardinia (23,949 km²), Sicily (25,662 km²), Corsica (8,741 km²) and Crete (8,312 km²). Found here also are the major island groups of the Balearic Islands of the western Mediterannean, the islands of the eastern Adriatic and the myriad islands the Aegean Sea.
Important island groups are located along the eastern margins of the Atlantic: the Madeira Islands, British Isles, Canary Islands and the Cape Verde Islands.
The few islands found in the open waters of the Atlantic lie widely scattered along the mountainous bulge of the Mid-Atlantic Ridge — a 10,000 km long divergent plate boundary rising up to 3 km above the ocean floor. These mountainous islands include the Azores, Iceland, St. Helena, the Tristan da Cunha Group, Gough Island and Bouvetøya.