地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
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飛騨山脈槍穂高連峰南岳周辺の周氷河性平滑斜面における気温・表層地温と礫質ローブ形成プロセスの検討
青山 雅史
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ジャーナル フリー

2012 年 121 巻 2 号 p. 342-358

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 Air and ground temperatures on a periglacial smooth slope at Mt. Minamidake (3,033 m a.s.l.), northern Japanese Alps, were observed and used to compare periglacial conditions between alpine areas in Japan and Switzerland. These temperature data were combined with morphometric parameters to discuss periglacial processes forming a bouldery lobe and a pebbly lobe on the smooth slope.
 Freezing indices at the study site are smaller than indices in permafrost areas of Mt. Fuji and of the Daisetsu Mountains, Hokkaido. Mean annual air temperatures at the study site were within the boundary values for the presence of mountain permafrost. Mean annual ground surface temperatures on the studied slope are comparable to or colder than those at the lower limit of permafrost in the Swiss Alps. Thus, ground surface temperatures on the studied slope indicate the presence of permafrost, unless an advective heat flow such as rainwater infiltration disturbs subsurface temperatures. The bouldery lobe has a smaller riser height than a typical rock glacier, but a larger one than a typical solifluction lobe. The morphometric parameters of the pebbly lobe are comparable to typical solifluction lobes, which originate from annual frost creep and gelifluction. The surface of the bouldery lobe lacks interstitial fine materials, and that of the pebbly lobe is partly composed of a fine debris layer. These conditions suggest that permafrost creep is responsible for the development of the bouldery lobe, while the pebbly lobe originates from annual frost creep and gelifluction.

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© 2012 公益社団法人 東京地学協会
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