Author's Organization：Graduate school of Science and Technology, Niigata University Department of Geoscience, Faculty of Science and Engineering, Shimane University Department of Geology, Faculty of Science, Niigata University
Published: December 15, 2000Received: April 14, 2000Available on J-STAGE: April 11, 2008Accepted: September 06, 2000
Advance online publication: -
Revised: -
Fission-track age determination on the Cenozoic marine sedimentary sequences distributed in the Shinjo Basin, Yamagata Prefecture was carried out. Though the upper Sakekawa and Oriwatari Formations have been considered to be late Pliocene-Pleistocene in previous researches, the present result of FT dating on the volcanic tuffs intercalated in the basal part of the Oriwatari Formation showed 4.3-4.6 Ma the early Pliocene age.
