Coastal and Oceanic Landform (04.Atoll)

04.Atoll                                                                                                   Back to Coastal and Oceanic Landform


  • An atoll is a coral island /or islands.
  • Atoll islands are low lying, with their elevations less than 5 m. 
  • An ancient atoll as a hill in a limestone area is called a reef knoll. 
  •  The largest atoll is Huvadhu Atoll in the south of the Maldives.
  • The second largest atoll by dry land area is Aldabra.


atolls of the Maldives, which consists of 1,322 islands arranged into 26 atolls.
atolls of the Maldives, 1,322 islands  26 atolls.


  • Most of the world's atolls are in the Pacific Ocean.with concentrations in;
                    -Tuamotu Islands
                   -Caroline Islands
                   -Marshall Islands
                   -Coral Sea Islands
                   -Island groups of Kiribati
                   -Tuvalu
                   -Tokelau


  •   Indian Ocean;

                -Atolls of the Maldives

                -Laccadive Islands
               -Chagos Archipelago
              - Seychelles 


  • The Atlantic Ocean has no large groups of atolls.
  • examples of other  atolls;

              -East of Nicaragua,Caribbean Sea.

Atafu atoll in Tokelau in the Pacific Ocean
Atafu atoll in Tokelau in the Pacific Ocean
              -Kure Atoll
              -Northwestern Hawaiian Islands
              -Elizabeth Reef
              -Middleton Reef in the Tasman Sea
              -Ducie Island
             -Pitcairn Islands
             -Bermuda

The largest atolls by total area  are
  • Saya de Malha Bank, Western Indian Ocean
  • Lansdowne Bank, west of New Caledonia
  • Chesterfield Islands, New Caledonia
  • Great Chagos Bank 
  • Reed Bank, Spratly Islands 
  • Ardasier Bank, Spratly Islands
  • Macclesfield Bank, South China Sea 
  • North Bank (Ritchie Bank, north of Saya de Malha Bank
  • Rosalind Bank, Caribbean Sea 
  • Sabalana Islands, Indonesia
  • Nukuoro atoll, Federated States of Micronesia
  • Lihou Reef, Coral Sea
  • Diamond Islets Bank, Coral Sea
  • Bassas de Pedro
  • Kwajalein, Marshall Islands
  • Namonuito Atoll, Chuuk 
  • Truk Lagoon, Chuuk
  • Maro Reef, Northwestern Hawaiian Islands
  • Rangiroa, Tuamotu Islands
  • Boduthiladhunmathi Atoll, Maldives 
  • Huvadhu Atoll, Maldives
  • Kolhumadulhu Atoll, Maldives
  • North Malé Atoll, Maldives
  • Ari Atoll, Maldives
  • Ontong Java, Solomon Islands 

 Pacific Remote Islands Marine National Monument.
 Pacific Remote Islands Marine National Monument.


No comments:

Post a Comment