Pseudo-atoll
Encyclopedia
A pseudo-atoll, like an atoll
, is an island of coral
that encircles a lagoon
partially or completely. A pseudo-atoll differs from an atoll as established by several authorities.
s not formed as a result of subsidence
. 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.
as an example.
Atoll
An atoll is a coral island that encircles a lagoon partially or completely.- Usage :The word atoll comes from the Dhivehi word atholhu OED...
, is an island of coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
that encircles a lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
partially or completely. A pseudo-atoll differs from an atoll as established by several authorities.
Definitions
Alexander Agassiz gave the term pseudo-atoll to any ring-shaped reefReef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s not formed as a result of subsidence
Subsidence
Subsidence is the motion of a surface as it shifts downward relative to a datum such as sea-level. The opposite of subsidence is uplift, which results in an increase in elevation...
. while Norman D. Newell
Norman D. Newell
Norman Dennis Newell was professor of geology at Columbia University, and chairman and curator of invertebrate paleontology at the American Museum of Natural History in New York.-Personal life:...
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 PseudoatollEverglades Pseudoatoll
The Everglades Pseudoatoll 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 paleodepression possibly created by an asteroid impact upon the carbonate Florida Platform at the southern part...
as an example.