Zircon U-Pb and reassessed zircon fission track ages of Miocene Mizunami and Iwamura Groups in the southeastern part of Gifu Prefecture, central Japan

Abstract

Here U–Pb and reassessed fission track (FT) ages are presented for samples from the Miocene Mizunami and Iwamura groups in the southeastern Gifu Prefecture, central Japan. The U–Pb ages of three tuff samples coincide with the reassessed FT ages within the error range. These new U–Pb and reassessed FT ages are consistent with those reported in previous microfossil and paleomagnetic studies, which indicate the following depositional history: The Hongo and Akeyo formations of the Mizunami Group were deposited at ~19–18 Ma and ca. 18 Ma, respectively, and the lower part of the Toyama Formation of the Iwamura Group was deposited ca. 18 Ma.