A tabulation of K-Ar, Rb-Sr and Pb-alpha ages obtained for materials within the United States (including Alaska and Hawaii) during the years 1969 through 1971

This tabulation of ages has been made as a convenience to anyone desiring a quick reference to ages published in the United States from 1969 through 1971. This tabulation does not include all published K-Ar, Rb-Sr, or Pb-α ages but is probably 98% complete. Many of the radiometric ages published in abstracts, footnotes, or personal communications are not included as sample localities are lacking or are not sufficiently detailed to be of value. Such ages are often published in a subsequent article with detailed sample locations and geologic interpretation. There may be some duplication of ages in this tabulation. The references listed are either the original source for an age or the best source in regard to sample location, decay constants, interpretation, etc. A few fission-track ages also are listed.