1991 Fiscal Year Final Research Report Summary
Changes of Slope Stability in the Mountains during the Holocene, viewed from Inorganic Content and Decomposition Degree of Peat Deposites.
| Project/Area Number |
02680201
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
自然地理学
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| Research Institution | Nara Women's University |
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Principal Investigator |
SOHMA Hidehiro Nara Women's University, Faculty of Letters, Associate Prof., 文学部, 助教授 (90196999)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Peat layer / Inorganic content / Decomposition degree / Holocene / Climatic change / Slope stability / Deforestation |
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| Research Abstract |
In the report, features of deposits at three peatlands are discussed. One(Gakinotanbo)is situated in the snow-rich Northern Japanese Apls, and others(Okamekie peatland and Oodai-ga-hara)are in the Kii Mountains where have a little snowfall in winter season.
Results are summerised sa follows :
(1)12000yr. B. P. to 8000yr. B. P.
Peat began to deposit at the Gakinotanbo Peatland. Severe mudfolws from the outside of the peatland frequently occvred during this period, which suggests unstable slope conditions in the Northern Japanese Apls.
(2)8000yr. B. P. to 3-4000yr. B. P.
Gakinotanbo Peatland spread to the outside and influences of mudflows decreased except marginal places. Beginning of this stage roughly corresponds to onset of peat deposition in peatlands, located on the gentle slope in the alpine zone and on the gentle piedmont slopes in the subalpine zone and montane zone in the the Northern Japanese Apls. Peat layer of this stage contains many wood particles, which suggest rather dry condition and frequent occurrences of heavy rainfall during the snow-free season.
(3)3-4000yr. B. P. to present
At the Gakinotanbo Peatland, influences of mudflows decreased even at the marginal and peat layer has changed to umdercomposited. Those are considered to have been reflected not only the delay of snow melting caused by the little lowering of temperature, also decrease in occurrences of heavy rainfall.
At beginning of this stage, the Okameike peatland where winter snowfall mainly brought by the low pressures along the Pacific coast has changed from the pond to the peatland synchronously.
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