Geology on tropical islands

Geology

Oceanic islands exist mainly in two geological types or a combination thereof: volcanic islands, which are in fact the tips of subsea volcanos, and coral islands, built of limestone which one day was deposited below sea level by coral reefs and which was subsequently uplifted above sea level.

Reworking of eroded debris of each of these rock types results in other sedimentary rock being deposited on these islands, as well as direct chemical precipitates such as salt.

A very special type of rock occurring on oceanic islands in the tropical belt are phosphate rocks.



c100/updated 2004-12-28