| Two different types of shark fossil assemblages occur at the same beds in the same locality. The fossiliferous beds of shark teeth were deposited in upper Piacenzian. However, the Zukawa Formation was deposited through whole Piacenzian and uppermost Zanclean (4.04 - 2.55 Ma). The beds contain shark teeth as granule to pebble-sized gravel. Therefore we consider that the most shark teeth fossils are reworked from the lower part of the Zukawa Formation and the Yachi Formation (Miocene). |
| Upper Pliocene |
| Probably reworked from the Yachi Formation (Miocene) |
| The upper part of the Zukawa Formation: Upper Piacenzian, 2.75 - 2.55 Ma 2.75 Ma: Datum A, the floral change from Reticulofenestra spp. (small) assemblage to Coccolithus pelagicus assemblage 2.55 Ma: The top of calcareous nannofossil Zone NN16 Amano, K., Hamuro, M., Hamuro, T., Sato, T. and Ogihara, R. (2012) Influence of the latest Pliocene cooling to the benthic fauna from the central part of the Japan Sea borderland: Molluscan fauna from the Zukawa Formation in Toyama Prefecture. Jour. Geol. Soc. Japan, 118(12), p.810 - 822. |
Back & Forth
20231125