Hillslope Development and Sediment Yield under Changing Environment since 46, 000 years B. P. in the Kawadoi Basin, Northeast Japan
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- NAKAYAMA Tomoko
- 株式会社 きもと
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- MIYAGI Toyohiko
- 東北学院大
Bibliographic Information
- Other Title
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- 閉鎖系堆積物からみた最終氷期中葉以降の環境変化と斜面発達過程
- ヘイサケイ タイセキブツ カラ ミタ サイシュウ ヒョウキ チュウヨウ イコウ
- 山形県川樋低地
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Abstract
Little has been worked on history of slope denudation under environmental changes of late Quaternary in humid temperate area like Japanese Islands.<br>We gave it general consideration of the history of local geomorphic environments and hillslope instability based on micro landform classification (Fig. 2), and analyses of sediments located in isolated small basin, called Kawadoi basin, Yamagata Prefecture.<br>Slope deposits are often interbeded with peat layers in the lowland and the peat layers provide adequate materials for pollen analyses and radiocarbon datings which enable to establish chronology of environmental changes. So there are close relationships between micro landforms and vegetation, that hillslope instability in the past also will be guessed by the fluctuations of pollen diagram. The main results are as follows;<br>1. Several periods of hillslope instability are identified by the analyses of cross sections (Figs. 3 and 4), i. e.<br>1) 46, 000-37, 000yr B. P., 2) 29, 000-27, 500yr B. P.<br>3) 27, 000-12, 500yr B. P. including the especially large sediment yield period at the age of 27, 000yr B. P., 4) 11, 000-8, 700yr B. P., 5) about 6, 000yr B. P., and 6) after 3, 000yr B. P..<br>2. On the basis of pollen diagram, the sediment is into four local pollen assemblage zones (MG, FG, L and R) including 12 sub-zones (Fig. 6 and p. 30).<br>3. Sediments yield periods are contemporal with the phase of changes of climate such as coldward age, warmward age and the Hypsithermal.<br>4. The Extra local pollen and Local pollen such as Betula, Carpinus, Zelkova and Ulmus, Fraxinus, Juglans and Pterocarya stands on the unstable slopes. These pollen are well included in inorganic horizons.
Journal
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- Annals of The Tohoku Geographycal Asocciation
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Annals of The Tohoku Geographycal Asocciation 36 (1), 25-38, 1984
THE TOHOKU GEOGRAPHICAL ASSOCIATION
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Details 詳細情報について
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- CRID
- 1390001205147893376
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- NII Article ID
- 130001075094
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- NII Book ID
- AN00168742
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- ISSN
- 18841244
- 03872777
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- NDL BIB ID
- 2980962
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed