In warm, tropical oceans, like that shown in (A), large numbers of corals and other marine animals and plants make skeletons out of calcite and other carbonate minerals. These skeletons and carbonate mud make a rock called limestone like the one shown in (B) from San Salvador Island in the Bahamas. This limestone was a coral reef living under a shallow sea about 120,000 years ago.
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(A) Abi Howe, American Geological Institute, courtesy of Earth Science World Imagebank and (B) courtesy of Lisa Gardiner
Last modified January 6, 2004 by Lisa Gardiner.
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