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A coral island is a type of island formed from coral detritus and associated organic material.〔(【引用サイトリンク】title=coral island )〕 They occur in tropical and sub-tropical areas, typically as part of coral reefs which have grown to cover a far larger area under the sea. ==Formation== Islands develop from coral reefs through one of two processes, uplift and accretion.〔 In uplift, part or all of the coral reef becomes Land as a result of the earth's crust rising above sea level.〔 In accretion, rocks and sand are layered on top of coral reefs during cyclonic storms, and the gradual accumulation of other solid material through the action of wind and waves leads to the development of the island.〔(【引用サイトリンク】title=Coral Reef... From the Beginning )〕 The process is later enhanced with the remains of plant life which grows on the island. Where coral islands form from atoll reefs, the result is an island or string of islands in a roughly circular form, surrounding a shallow lagoon. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Coral island」の詳細全文を読む スポンサード リンク
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