Lake Biwa sediments in Japan: Correlation of deep drilling cores and reconstruction of paleoenvironment during Quaternary

HR: 0800h
AN: PP31A-1514 [Abstracts]
TI: Lake Biwa sediments in Japan: Correlation of deep drilling cores and reconstruction of paleoenvironment during Quaternary
AU: * Takemura, K
EM: takemura@bep.vgs.kyoto-u.ac.jp
AF: Institute for Geothermal Sciences, Graduate School of Science, Kyoto University, Noguchibaru, Beppu, 874-0903 Japan
AU: Hayashida, A
PP31A-1514 AF: Science and Engineering Research Institute, Doshisha University, Kyotanabe, 610-0321 Japan
AU: Inoue, N
PP31A-1514 AF: Department of Geophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto, 606-8502 Japan
AU: Danhara, T
PP31A-1514 AF: Kyoto Fission Track Co.Ltd, Omiya-Minamitajiricho 44-4, Kita-ku, Kyoto, 603-8832 Japan
AU: Masuda, F
PP31A-1514 AF: Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto, 606-8502 Japan
AB: Lake Biwa is the largest freshwater lake in Japan, measuring 22.6 km side by 68 km long and having a maximum depth of 104 m. The lake has a long history from the early Pliocene based on the geological survey and paleogeographical study of lake sediments around Lake Biwa (Kobiwako Group). The sediments revealed the paleoenvironmental change and tectonic events at the convergent margin of the Eurasian plate since early Pliocene times. Deep drillings were carried out 1970's and 1980's in and around present Lake Biwa. These studies showed that the present Lake Biwa Basin bears a sedimentary sequence of about 900 m thickness, which were deposited in lacustrine or fluvial environments. Recently obtained fission-track age of tephra layer at deeper part in the present lake shows the continuous sedimentation of whole lake basin during Quaternary. After correlation of three deep core samples in lake basin and on land by tephrochronological method, we can figure out the paleotopography of the initiation of present Lake Biwa basin using seismic reflection records. Correlation of sequence in lake basin with that on land by precise tephrochronology and sedimentary sequence also shows the sedimentary reply at lake basin and shore to major glacial - interglacial cycles.
DE: 4914 Continental climate records
DE: 4926 Glacial
DE: 4936 Interglacial
DE: 4942 Limnology (0458, 1845, 4239)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005