Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

H (Human Geosciences ) » H-QR Quaternary research

[H-QR05] Quaternary, Diachronic dynamics of human-environment interactions

Sun. May 26, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Mamoru Koarai(Earth Science course, College of Science, Ibaraki University), Ken Ikehara(Institute of Geology and Geoinformation, National Institute of Advanced Industrial Science and Technology), Masayuki Hyodo(Research Center for Inland Seas, Kobe University)

[HQR05-P12] Characteristics of Latest Pleistocene to Holocene deposits of two cores obtained from the inner part of the Nobi Plain, central Japan

*Kodai Hasada1 (1.Faculty of Letters, Hosei University)

Keywords:sedimentary environment, radiocarbon age, floodplain, Holocene, Nobi Plain

The Nobi Plain, central Japan, is a Holocene fluvial–coastal plain formed mainly by the Kiso, Nagara, and Ibi rivers. This poster shows sedimentary characteristics of cores KG and OZ obtained from the inner part of the plain. Two cores were taken from the present floodplain of the plain where prodelta deposits are not distributed. The borehole sediments were divided into depositional units based on lithology, water content, color, mud content, radiocarbon age, and fossil diatom. KG1 and OZ1 are channel deposits composed mainly of sand and gravel. KG2 and OZ2 consist of silt to medium sand estimated to have accumulated under intertidal/subtidal environment near the river mouth, and overlay KG1 and OZ1, respectively. KG3, characterized by organic-rich mud, covering KG2 is interpreted as floodbasin deposits. OZ3, overlies OZ2, consists of coarse sand to very fine sand, and the upper part shows a fining-upward succession. This unit may have been formed under in-channel and point bar environment.