Pseudo-atoll Pseudo-atoll A pseudo-atoll, like an atoll, is an island that encircles a lagoon, 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, nor by 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. Alexander Agassiz gave the term pseudo-atoll to "any ring-shaped reefs 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
Haa Dhaalu Atoll Haa Dhaalu Atoll Haa Dhaalu Atoll is the code name based on the letters of the Maldivian alphabet commonly used to refer to the administrative division (known as "Atoll") officially known as South Thiladhunmathi Atoll (Maldivian: "Thiladhunmathi Dhekunuburi") in the Maldives. The administrative division consists of the southern section of natural Thiladhunmathi Atoll (which is shared with North Thiladhunmathi (Haa Alifu) Atoll) and Makunudhoo or Maamakunudhoo Atoll (Malcolm Atoll in the Admiralty Charts) with its large reef. The capital of the administrative division is Kulhudhuffushi. Thiladhunmathi Atoll was divided into northern and southern divisions on 21 May 1958, thus creating