The islands are formed around a ring shaped coral reef encircling a lagoon. This reef structure, typical of Maldives, is called an atoll. In fact, the English word 'atoll' itself is derived from the Maldivian or dhivehi word for it-atholhu. There are 26 natural atolls in the Maldives.
(http://www.maldiveisle.com/geography.htm)
Atoll Formation:
The atolls of the Maldives are formed from coral structures, separated by lagoons. The atolls are in fact part of a greater structure known as the Laccadives-Chagos Ridge, which stretches over 2000 kilometres. The islands are low lying with the highest point at approximately 8 feet above sea level. (http://www.vermillionmaldives.com/maldives-geography.htm)
There are still ongoing debates about the formation of atolls. According to Charles Darwin's theory, when submerged volcanoes rise from the sea, a coral reef grew on its edge. When the volcanoes submerged, the coral reefs encircling a water-filled basin remained. Consequently, islands were formed on the reefs as the tides and currents brought dead coral onto sandbars. These were in turn colonised by plants.
Coral reefs barriers
Six inches deep humus forms the initial layers of the soil. Sandstone of about 2 feet is found below and after it sand is accompanied with fresh water. The salinity of the soil along the beach restricts the growth to few plants. Normally, shrubs and small hedges occupy the area.
Depositional landforms- Beaches of the Maldives
Tides of the Maldives are eroding the Atoll islands and the Coral surrounding the islands.
Sources:
- Allen, C. (2016). Lecture 22: Coastal Landscapes, Personal Collection of C. Allen, University of Colorado Denver, Denver, CO.
- http://www.maldiveisle.com/geography.htm
- http://www.vermillionmaldives.com/maldives-geography.htm
- Tides of Maldives : http://www.tide-forecast.com/countries/Maldives
