Stratigraphy and 14C age of the Holocene deposits in the Kurihama area, eastern part of the Miura Peninsula, south-central Japan
Science Report of the Yokosuka City Museum 1992(40): 25-29
Approximately 50 m thick Holocene deposits are distributed along the subsurface of the Hirasaku Valley in Kurihama of Yokosuka City in the eastern part of the Miura Peninsula. The Denpukuji-ura Site whose ground surface is ca. 5 m above sea-level is located at the entrance of a branch of the Hirasaku Buried Valley. The remains are buried in a natural shell bed. The bed composed of 4 m thick fine-grained sand is divided into layers, I, II, III and IV, in ascending order. Layer IV is unconformable with the basement and conformable with Layer III. Layer II covers unconformable Layer III which is partly overlain by Layer IV. The remains were collected from Layers III and II. The 14C age of Layers IV, III and II is approximately 5000 yBP. The Iri deposit is located in the uppermost part of the valley geomorphology. The top of the marine shell bed is at 8 m above sea-level, 3 m higher than the Denpukuji-ura Site. The Iri deposit is composed of granule-bearing shelly fine-grained sand (4.26-8.07 m above sea-level), coarse-grained sand (8.07-8.95 m), granule-bearing peat (8.95-9.34 m) and peat (9.34-1 0.01 m), in ascending order. The 14C ages are 7130-4910 yBP for the fine-grained sand, 3600-3420 yBP for the granule-bearing peat, and 2190 yBP for the peat, respectively. The sea-level at the time of ca. 5000 yBP was at 8 m in the Iri area, corresponding to 5.0-3.5 m in the Denpukuji-ura Site.