Coral Chronometers: Seasonal Growth Bands in Reef Corals

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Science  21 Jul 1972:
Vol. 177, Issue 4045, pp. 270-272
DOI: 10.1126/science.177.4045.270


Autoradiagraphs and x-radiographs have been made of vertical sections through the centers of reef corals from Eniwetok. Radioactivity bands in the coral structure are caused by strontium-90 and are related to specific series of nuclear tests, thus making possible calculation of long-term growth rates. These data indicate that the cyclic variations in radial density revealed by x-radiography are annual.

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