1994 Fiscal Year Final Research Report Summary

Physically-based-dating for pond sediments

Research Project

Project/Area Number	05558006
Research Category	Grant-in-Aid for Developmental Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	自然地理学
Research Institution	Kanazawa University
Principal Investigator	KASHIWAYA Kenji Kanazawa Univ., Dep.Earth Sciences, Assoc.Prof., 理学部, 助教授 (30161029)
Co-Investigator(Kenkyū-buntansha)	AOKI Tohru Kyoto Univ.RI Center, As.Prof., 放射性同位元素総合センター, 助手 (70027051)
Project Period (FY)	1993 – 1994
Keywords	SEDIMENT / ARTIFICIAL NUCLIDE / EROSION / CATCHMENT / HEAVY RAINFALL / 侵食
Research Abstract	Analyzes of physical properties in pond sediments show that the remnant of mass movements can be traced in the grain-size sequences of sediments in the drainage areas where there have beeen heavy rainfalls in 1964 ; the years of mass movements due to heavy reinfalls show up as prominent coarsening in the grain-size distribution. The date is estimated with the ^<137>Cs concentration ; the peaks (about 1962) in the concentration of sediment sequences from three ponds are assumed to be in the same phase of sedimentary environment. Grain size variations in the ponds in each area show similar tendency ; there have been similar sedimentary and/or hydro-erosional conditions. Average sedimentation rate during past 30 years in the center of sampling ponds, which can be calculated by the use of 137Cs, is closely related to geomorphological settings in each drainage basin.

(4 results)