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尾瀬ヶ原における地溏の拡大とその速度の測定
福原, 晴夫;永坂, 正夫;藤原, 英史;野原, 精一
Permalink : http://hdl.handle.net/2115/85011
JaLCDOI : 10.14943/lowtemsci.80.79
KEYWORDS : 高層湿原;池溏;池溏岸;拡大;ケルミ－シュレンケ複合体;mire;pool;expansion speed;shoreline;bank and hollow complex
Abstract
尾瀬ヶ原（標高；1,400ｍ，長さ；6km，幅；2km，面積；7.6km2）は本州最大の高層湿原で約1,800個の大小様々な池溏が分布している．高層湿原の多様な形態の池溏は，ケルミ－シュレンケ複合体（指紋状パターン）の連合を通じて形成されてきたと推定されている．尾瀬ヶ原においても，同様な過程が考えられる．岸辺の抉れ状態，池溏岸の開裂や離脱の状況，洪水による岸辺泥炭の攪乱や剥離，過去の映像との比較，過去の池溏形態計測との比較，固定島の形成過程，水深と水生植物の分布，ヒツジグサのへりなし型分布の成因などから池溏拡大に関する事象について検討した．次いで，二つの仮定を基に池溏岸の拡大速度の推定を試みた．4池溏の調査から平均1.5cm 年-1であると推定し，その妥当性について検討した．
The Ozegahara mire (alt. 1,400m，length 6 km，width 2 km，area 7.6 km2) is the biggest one in the Honshu in Japan，embracing about 1,800 pools. It has been estimated that morphological varieties of pools in peat mire are formed based on the conjugation of the bank and hollow complexes (fingerprint like pattern). We examined the various phenomenon expressing enlargement of pool shore such as depression under shore， cleavage and separation of shoreline，disturbance and peeling of shore surface by flooding，comparison of past aero photographs，comparative morphological measurements of pools done in 1950 and 1997，formation process of fixed islands in pools，relationship between macrophyte distribution and bottom form and distribution of Nymphaea tetragona in pool margin. The rates of shoreline enlargement were estimated based on simple two hypotheses for four pools.
The Ozegahara mire (alt. 1,400m，length 6 km，width 2 km，area 7.6 km2) is the biggest one in the Honshu in Japan，embracing about 1,800 pools. It has been estimated that morphological varieties of pools in peat mire are formed based on the conjugation of the bank and hollow complexes (fingerprint like pattern). We examined the various phenomenon expressing enlargement of pool shore such as depression under shore， cleavage and separation of shoreline，disturbance and peeling of shore surface by flooding，comparison of past aero photographs，comparative morphological measurements of pools done in 1950 and 1997，formation process of fixed islands in pools，relationship between macrophyte distribution and bottom form and distribution of Nymphaea tetragona in pool margin. The rates of shoreline enlargement were estimated based on simple two hypotheses for four pools.
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