Bulletin of the Mizunami Fossil Museum

Bulletin of the Mizunami Fossil Museum Vol. 50, No. 3 Research reports of the “Paleoparadoxiid Mizunami-Kamado specimen”

Preliminary report of strontium isotopic ages of molluscs from the locality of the “Paleoparadoxiid Mizunami-Kamado specimen” in Mizunami City, central Japan

Daisuke Araoka, Toshihiro Yoshimura, and Rei Nakashima

Published: 2024/3/29   Page: 13–16

Paleoparadoxiid fossils were discovered in the Shukunohora Formation of the Mizunami Group exposed in the Toki River bed in Shimogiri-ku, Kamado-cho, Mizunami City, in 2022. In order to clarify the age of the Shukunohora Formation in this locality, we determined stron-tium isotopic ages using shell fossil samples that were cooccurred with paleoparadoxiid fossils. The strontium isotopic ages suggest that the depositional age of the paleoparadoxiid-bearing horizon is ca. 16.5 Ma.