JpGU-AGU Joint Meeting 2020

Presentation information

[J] Poster

H (Human Geosciences ) » H-QR Quaternary research

[H-QR05] Natural hazard and human activity recorded in underwater geoarchaeological structure

convener:Wataru Tanikawa(Japan Agency for Marine-Earth Science and Technology, Kochi Instutute for Core Sample Research), Tokuyama Hidekazu(Center for advanced marine core research, Kochi University), Shintaro Yamasaki(Disaster Prevention Research Institute, Kyoto University)

[HQR05-P02] Characteristics and its significance of marine cores collected from inner Uranouchi Bay, Kochi Prefecture

*Masafumi MURAYAMA1, Wataru Tanikawa2, Akira Ijiri2, Tatsuhiko Hoshino2, Takehiro Hirose2, Toshiya Fujiwara2, Kazuya Kitada2, Kastuya Nejigaki3, Tokuyama Hidekazu4, Go-Ichiro Uramoto4, Kazuno Arai4, Kondo Yasuo3, Yuhji Yamamoto4, Research Member Kurodagoori4 (1.Faculty of Agriculture and Marine Science, Kochi University, 2.JAMSTEC, 3.Graduate School of Integrated Arts and Sciences, Kochi University, 4.Center for Advanced Marine Core Research, Kochi University)

Keywords:Kuroda-Gori archeological survey, Uranouchi Bay, Event Sediments

For the purpose of the Kuroda-Gori archeological survey, sediment cores collected from the inner part (10m depth) of Uranouchi Bay, Kochi Prefecture, were analyzed. The history of changes in the marine environment and biota at that time was also restored. Uranouchi Bay, located in the central part of Tosa Bay, Kochi Prefecture, faces the north side of the Yokonami Peninsula, is elongated in the east and west, and is known as a sinking bay with a depth of 12 km. A 4-m sediment core was collected by vibro coring using the Kochi University research vessel "Nechun". Since the sampling point was not affected by the surrounding river, this core sample is considered to have recorded detailed environmental changes in the bay. The collected core samples were subjected to X-ray CT and MSCL analysis, and then halved to describe the naked eye and to collect and identify frequently occurring shellfish. The lithology of the sediment is olive-colored sity clay, which generally contains many shell pieces. The area near the upper part of the core was dark and had a strong hydrogen sulfide odor. In addition, event deposits with well-developed grains are observed in the lower part of the core, and the origin of the deposits will be examined in the future.