Abstract
The stratigraphy of the Tokyo Formation at the type core section in the Yoyogi park, Tokyo, central Japan is reexamined based on the sedimentary facies and tephro- and palyno-stratigraphy.
Sedimentological study of the type core section and geotechnical borehole data analysis reveal that the Tokyo Formation can be divided into the lower incised-valley fills and the upper flattened, widespread marine sand bed. These constitute a depositional cycle formed during a series of transgression and regression. The Tokyo Formation is covered with the Shimosueyoshi Loam intercalating a KlP tephra layer (late MIS 5e). Pollen assemblages in the lower part of the Tokyo Formation are comparable with those of early to middle MIS 5e in the off Kashima seafloor core. Therefore, the Tokyo Formation at the type core section is considered to have been mainly deposited during MIS 5e and can be correlated with the Kioroshi Formation in the northern Chiba area and the succession of the Setagaya and Tokyo formations in the Setagaya area. However, further stratigraphic examination of the Tokyo Formation is required because it is not necessary equivalent to the strata previously called the Tokyo Formation in other areas of Tokyo.
