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Title
  • ja 立山追分の孤立した池塘の成因とその形成時期について
Alternative
  • en On the origin of the isolated pond in Tateyama Oiwake and the time of its formation
Creator
    • ja 朴木, 英治
    • ja 加藤, 咲
Subject
  • Other 池塘
  • Other 堤防
  • Other 風成塵
  • Other 泥炭
  • Other 柱状図
  • Other Pond
  • Other embankment
  • Other eolian dust
  • Other peat
  • Other columnar section
Description
  • Other The ground surface and underground structure of the pond, which exists independently in Tateyama Oiwake, were investigated, the heights that seemed to be clay layers were lined up from the north to the east of the pond just below the embankment surrounding the pond on the surface. However, there were few such topography from the south to the southwest of the pond. From the geological formations and dating of the soil core in and around the pond, it is estimated that the formation of the pond started before 14027calBP -13754calBP and 13625calBP -13615calBP, and then the surroundings are often transported during the cold season. It is estimated that dust (yellow sand, etc.) piled up and peat formation began about 8000 years after the end of the cold season, and it became the current topography. The water depth around 7300 years ago when the Akahoya volcanic ash from this pond came in was estimated to be about 30 cm, which was deeper than the current 10 cm. In addition, there is a place where the part estimated to be the bottom of the pond at that time is now a dike, and it is possible that its shape changed during the formation process.
  • Other 立山追分で全く独立して存在している池塘について、ピンポールによる地下構造の調査、コア採取と粒子計測、年代測定を行った結果、地表の堤防直下に比較的硬い粘土で形成された高まりがあり、最終氷期に形成された堤防の名残と考えられた。池塘の形成開始は14027 – 13754 calBPよりも前と推定され、形成のきっかけについては不明であった。最終氷期の間は集水域の泥炭層が薄く、流入水量が池塘の大きさに比べて大きくなったため池塘底堆積物が堆積しにくく、堤防やその外の斜面上での風成塵などの堆積速度の方が大きくなり、水深が増加した。温暖期になって集水域に泥炭が厚く形成されるようになると流入水量が低下し、池塘底の堆積が堤防や斜面などよりも早く進み、水深が浅くなって現在に至ったと考えられた。この池塘の鬼界アカホヤ火山灰が飛来した7300年前頃の水深は最大で30 cm程度と推定された。
Publisher 富山市科学博物館
Date
    Created2021-04-08 , Issued2021-07-01
Language
  • jpn
Resource Type departmental bulletin paper
Version Type VoR
Identifier URI http://repo.tsm.toyama.toyama.jp/?action=repository_uri&item_id=2019
Relation
  • isIdenticalTo NAID 120007097302
Journal
    • NCID AA12306127
    • ISSN 1882-384X
      • 富山市科学博物館研究報告 = Bulletin of the Toyama Science Museum 45, 25-36
File
Oaidate 2022-10-02