The atolls of the Maldives were formed over a period of several million years. As is the case with other atoll groups, the Maldive atolls were formed when a huge mountain range submerged.
At one point, this mountain range was above sea level but when it began to submerge it must have done so incredibly slowly for coral reefs grow at the unbelievably slow pace of about one centimetre per year. The size of the volcano that submerged can be imagined when one flies over an atoll, for at one time the atoll ring was fastened to the slope of the volcano. From there the reef grew vertically.
It must be remembered that coral can only grow within fifty metres of the ocean surface and requires ocean water that is between 20 degrees and 27.7 degrees Celsius.
Monsoon winds and ocean currents can have an influence on the shape and development of the coral reefs.
The reef is wishbone shaped. In the middle of the island there is a lagoon with water that is approximately the same hue as that of the ocean. In the case of the lagoon, the sun does not reach the bottom so it looks just as deep as the ocean appears to be.
The two dark, boomerang-shaped pieces are land The white line, which is on the western and southern sides of the atoll suggest that the prevailing winds are blowing from out of the west.
This atoll was once an island with a volcano in the centre of it. As the island submerged, ever so slowly, the reef continued to grow, at a snail's pace. Once the volcano sank out of sight, an atoll appeared. It may take as long as thirty million years for an atoll to form.
This graphic shows an aircraft flying over an island with a huge fringing reef.
There are 425 atolls in the oceans and 77 of them are in the Tuamotus.
Taiaro completely enclosed lagoon
Anuanurunga accessible lagoon
Mataiva a lagoon with a network of coral structures
Reef Composition and Formation