A tombolo (Italian, from Latin tumulus – mound) or sometimes ayre (Old Norse Eyrr – gravel beach) is a deposition landform in which an island is attached to the mainland by a narrow piece of land such as a spit or bar. Once attached, the island is then known as a tied island. Tombolos usually form because the island causes wave refraction, depositing sand and shingle moved by longshore drift in each direction around the island where the waves meet. Eustatic sea level rise may also contribute to accretion as material is pushed up with rising sea levels. This is the case with Chesil Beach (which connects the Isle of Portland to Dorset in England), notable because the shingle ridge is parallel rather than perpendicular to the coast.

List of notable tombolos

• Mare Island, Vallejo, California
• Mersey Point, Shoalwater, Western Australia
• The isthmus at Aden, Yemen
• Aupouri Peninsula, New Zealand
• Barrenjoey Headland, Pittwater, New South Wales, Australia
• Chappaquiddick Island, Martha's Vineyard, Massachusetts
• Charles Island, Connecticut
• Chesil Beach, Dorset, England
• Cheung Chau, Hong Kong
• Fingal Bay, New South Wales, Australia
• Gwadar, Pakistan
• Howth Head, Dublin, Ireland
• Kapıdağ Peninsula, Balıkesir, Turkey
• Kettla Ness, Burra, Shetland Islands, Scotland
• Llandudno, Wales
• Maharees, Dingle Peninsula, Ireland
• Miquelon, Saint-Pierre and Miquelon
• Monemvasia, Laconia, Peloponnese, Greece
• Mount Maunganui, New Zealand
• Nahant, Massachusetts (a natural tombolo, but connected to the mainland by a causeway)
• Palisadoes, Kingston, Jamaica
• Presqu'ile Provincial Park, Ontario, Canada
• Quiberon, France
• St Ninian's Isle, Shetland Islands, Scotland
• Ayre o Swinister , Shetland Islands, Scotland
• Yei of Huney, Huney, Shetland Islands, Scotland
• Langness, Castletown Bay, Isle of Man
• Cádiz, Andalucía, Spain
• Las Palmas de Gran Canaria, Canary Islands, Spain
• Hakodate, Hokkaido, Japan
• Mount Taipingot, Rota, Northern Marianas
• Monte Argentario , Tuscany coast, Italy

See also

• Ayre
• Isthmus
• Bar

External links

• Geology.About.com's page on tombolos (useful for its descriptive photograph)
• Photograph: Chesil Beach
• Photograph: Chesil Beach and the Isle of Portland
• Tombolos or ayres in the Shetland Islands