Tied island

Not to be confused with Tidal island.

View from the Isle of Portland looking towards the mainland of Great Britain. Chesil Beach on the left connects the tied island to the mainland.

St. Ninian's Isle, a tied island in all but the highest tides

Tied islands, or land-tied islands as they are often known, are landforms consisting of an island that is connected to land only by a tombolo: a spit of beach materials connected to land at both ends. St. Ninian's Isle, in the Shetland Islands off the north coast of Scotland is an example of this; it was once an island but is now linked to the mainland. Other examples include: North Island, San Diego, California, Barrenjoey, New South Wales in Australia and Wedge Island in Western Australia.

The Isle of Portland is also referred to as a tied island, although technically, geographers now believe that Chesil Beach which connects it to the mainland is a barrier beach which has moved eastwards, rather than a tombolo, which would be formed by the effect of the island on waves.

References

• Glossary of geology and related sciences. Jesse V. Howell, American Geological Institute. 1962.
• Some Coastal Landform Definitions. Matthew Flinders, Villanova College, Queensland.

External links

• Media related to Tied islands at Wikimedia Commons