Holocene deposits and buried topography in the coastal area of the eastern part of the miura peninsula south central japan
Science Report of the Yokosuka City Museum 36: 53-67
The writer has investigated the Holoecene series and buried topography of the east coastal area (Yokosuka .apprx. Mabori Kaigan) of the Miura Peninsula in Tokyo Bay, through the analysis of the boring data recorded at the time of engineering work and also the existing materials. The buried topography of the east coastal area is characterized by continued V-shaped valleys that are narrow in width with steep slopes and running roughly from southwest to northeast. Between the valleys stretches the wave-cut bench which comprises three levels in terms of depth; namely, the first level (0 .apprx. +4m), the second level (-2 .apprx. -5 m) and the third levels (-6 .apprx. -10m). The Holocene series covering the buried topography is divided into the lower part consisting of basal graveland clay, and the upper part consisting of sand and sand-gravel, in ascending order. On the basis of the buried topography and the stratigraphy of the Holocene series of the east coastal area, the writer has reconstructed the paleo-geography by assuming three stages, that is, the early stage of the Jomon transgression, the culminant stage of transgression, and the regression and later stage. The molluscan assemblages in the reconstructed inner-bay environment are in harmony with the molluscan fauna constituting the Jomonage shell mounds existing in the east coastal area.