Continental islands lie off the large land masses that form continents. They lie on the continental shelf, which is the sloping, underwater ledge found at the edge of continents.
Continental islands were once part of a huge single land mass called Pangaea. Eventually, slow movements of the Earth’s crust broke Pangaea apart into several pieces that began to drift away. When the breakup occurred, some large chunks of land split from the bigger land masses. These fragments of land that were surrounded by the sea became islands.
Greenland and Madagascar are examples of continental islands that were formed in this manner. Other continental islands were formed because of changes in the sea level.
About 18,000 years ago, ice covered large parts of our planet. As this ice began to melt, the sea level rose. The ocean flooded many low-lying areas, creating islands such as the British Isles, which were once part of mainland Europe.
