title: Coral chronometers: seasonal growth bands in reef corals.
abstract: 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.
authors.forename: D W
authors.initials: DW
authors.lastname: Knutson
authors.forename: R W
authors.initials: RW
authors.lastname: Buddemeier
authors.forename: S V
authors.initials: SV
authors.lastname: Smith