赤石山脈三峰岳周辺の岩石氷河の^<14>C年代  [in Japanese] Radiocarbon dates for rock-glaciers around Mt. Mibudake, southern Japanese Alps  [in Japanese]

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Author(s)

    • 西井 稜子 NISHII Ryoko
    • 筑波大学生命環境系(井川演習林) Ikawa Forest, Faculty of Life and Environmental Sciences, University of Tsukuba

Abstract

永久凍土環境の指標地形である岩石氷河が日本アルプスで形成された時期を明らかにするために,赤石山脈三峰岳周辺において岩石氷河を構成する礫質土を採取し,その細粒分の<SUP>14</SUP>C年代を加速器質量分析法により求めた.三峰岳北面にある露頭において岩石氷河と基盤岩の境界(標高2,750m)から試料を3点採取した.そのうち2点が11cal ka BP, 1点が18cal ka BPを示した.一方,南面のカールを覆って発達する岩石氷河の下端急斜面上(標高2,650m)から得た3点のうち1点が10cal ka BPを示した.カールの形成時期と岩石氷河の発達に要する時間を考慮すると,三峰南面の岩石氷河が発達した期間はおもに晩氷期である可能性が高かった.三峰北面の岩石氷河についても,最終氷期最盛期から完新世初頭までのいずれかの時期の地形であることが判明した.

Two relict rock glaciers, which are indicators of a former permafrost environment, were <SUP>14</SUP>Cdated around Mt. Mibudake, southern Japanese Alps, using accelerator mass spectrometry. Three samples for dating were collected from the boundary between the deposit of the north rock-glacier and the underlying bedrock. Two of those samples indicate 11cal ka BP, and the other one indicates 18cal ka BP. A sample dated 10cal ka BP was also taken from the steep frontal slope of the south rock-glacier which fills a cirque bottom. Considering the timing of the cirque formation and the mechanisms of rock-glacier advance, we conclude that the south rock-glacier developed in the Late Glacial, whereas the timing of the north rock-glacier advance was sometime from the Last Glacial Maximum to the early Holocene.

Journal

  • The Quaternary Research (Daiyonki-Kenkyu)

    The Quaternary Research (Daiyonki-Kenkyu) 50(6), 309-317, 2011-12-01

    Japan Association for Quaternary Research

References:  41

Cited by:  2

Codes

  • NII Article ID (NAID)
    10030360252
  • NII NACSIS-CAT ID (NCID)
    AN0034136X
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    04182642
  • NDL Article ID
    023442532
  • NDL Call No.
    Z15-67
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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