Changes of Slope Stability in the Mountains during the Holocene, viewed from Inorganic Content and Decomposition Degree of Peat Deposites.

在报告中，讨论了三个泥炭地的沉积特征。其中一种(Gakinotanbo)位于日本北部积雪较多的Apls地区，另一种(Okamekie泥炭地和Oodai-ga-hara)位于冬季降雪较少的Kii山脉。血压降至8000年。B.P.泥炭开始在加基诺坦博泥炭地沉积。在此期间，泥炭地外部频繁出现严重的泥石流，这表明日本北部的坡面状况不稳定。(2)8000年。B.P.至3-4000年。B.P.Gakinotanbo泥炭地向外扩散，除边缘地区外，泥石流的影响减弱。这一阶段的开始大致对应于泥炭沉积的开始，泥炭沉积位于高山地带的缓坡上，以及日本北部APLS的亚高山带和山地带的山前缓坡上。这一阶段的泥炭层含有较多的木屑，表明无雪季节较为干燥，暴雨频繁发生。(3)3-4000年。在Gakinotanbo泥炭地，泥石流的影响即使在边缘也减少了，泥炭层已变为非复合泥炭层。认为这不仅反映了气温的小幅下降导致积雪融化的延迟，也反映了暴雨发生的减少。在这一阶段之初，主要由太平洋沿岸低压带来冬季降雪的冈美池泥炭地已经同步从池塘变成泥炭地。

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 presentAt 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.