Abstract
New evidence for correlation of three key tephra layers in the Quaternary strata between the Yokohama district and the Boso Peninsula, central Japan is provided. Strong coincidence of petrographic and chemical characteristics of tephra layers clearly demonstrates that the Sg 3 tephra layer in the Ofuna Formation and the Sg 2 and Sg 3 tephra layers in the Koshiba Formation in the Yokohama district can be correlated with the Kd 38, Kd 25 and Kd 24 key tephra layers in the Kiwada Formation in the Boso Peninsula, respectively. Biostratigraphic datums of calcareous planktons in the Ofuna-Koshiba Formations also support this result. Our study indicates that previous correlation of the Quaternary strata between the Yokohama district and the Boso Peninsula should be re-considered and detailed chronological studies of them will be needed in order to reconstruct basin evolution around the Kanto region during the Quaternary.
