Uranium-Series Ages of Pacific Atoll Coral.

The thorium-230: uranium-234 method of dating corals and oolites has been evaluated in detail for reliability, and various criteria have been established. Reliable ages for extensive coral formations of about 6000 and 120,000 years were obtained. A hiatus in the development of coral between 6000 and 120,000 years ago on the Pactfic atoll of Eniwetok implies that conditions did not permit coral growth during this period.