A pseudo-atoll, like an

atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most ...

, is an

island An island or isle is a piece of land, distinct from a continent, completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been ...

that encircles a

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') an ...

, either partially or completely. A pseudo-atoll differs from an atoll as established by several authorities, such as how it is formed (not by

subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope mov ...

, nor by

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

). It is considered a preferable term to "near-atoll". There is a need for rigorous definition of "pseudo-atoll" before it can be accepted as a general term.

Definitions

Alexander Agassiz gave the term pseudo-atoll to "any ring-shaped

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s not formed as a result of

". while Norman D. Newell and J. Keith Rigby called such reefs non-coral. and "We conclude that almost-atoll should be retained as a descriptive term as defined by Davis and Tayama, and that the use of "near-atoll" as a synonym be abandoned. The value of terms such as "semi-atoll" and "pseudo-atoll" needs close examination and more rigorous definition before being generally accepted." H. Mergner yet states that micro-atolls classify as pseudo-atolls. Professor David R. Stoddart of Berkeley states an "almost-atoll" is an atoll with a central island of left over residue.

Usage

Dr. Edward J. Petuch, author of ''Cenozoic seas: the view from eastern North America'', refers to pseudo-atolls as pseudoatolls with the

Everglades Pseudoatoll The Everglades Pseudoatoll (also called a pseudo-atoll) was a major geomorphic feature of southern Florida during the Pliocene epoch. Origin The Everglades Pseudoatoll began its growth during the early Eocene as a depression (geology), paleodepre ...

as an example.Petuch, Edward J., Cenozoic Seas: The View From Eastern North America, CRC Press; 1 edition (December 29, 2003), .

Definitions

Usage

See also

References

Further reading