Nora B. Shew Frederic H. Wilson 1982 <p>Early and preliminary results of potassiumargon dating work on samples from 12 sites in the Ugashik quadrangle indicate a continuation of the geologic trends seen in the Chignik and Sutwik Island quadrangles to the south (Wilson, 1980). Tertiary volcanic and hypabyssal rocks apparently fall into two age groups: early Tertiary-late Eocene to earliest Miocene and late Tertiary and Quaternary-late Miocene to Holocene (fig. 53). </p> application/pdf 10.3133/70180226 en U.S. Geological Survey Preliminary results of potassium-argon age determinations from the Ugashik quadrangle, Alaska Peninsula: A section in <i>The United States Geological Survey in Alaska: Accomplishments during 1980</i> reports