Findings on vegetation changes in the Ishikari Lowland, Hokkaido, from pollen analysis and AMS14C dating
| Autor: | Hoshino, Fusa, Haruki, Masahiro, Minami, Masayo, Nakamura, Toshio |
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| Jazyk: | japonština |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | 名古屋大学年代測定研究. 5:12-22 |
| Popis: | The 10.2 m core sample collected from the Higashinopporo Wetland, the east side of the Nopporo Hills in the central part of the Ishikari Plain, in 1997 has shown the presence of temperate deciduous broad-leaved forests and the continuous appearance of a small amount of Fagus crenata pollen. The authors collected the surface soil and conducted pollen analysis at 30 survey points set in 2020 within a range of 7 km east-west and 6 km northsouth from the three planted Fagus crenata parent tree groups in the Higashi-Nopporo Wetland region. The result indicates that fallen Fagus crenata pollen was confirmed at an appearance ratio of nearly 20% below the crown of the trees, while the ratio was just 0-1% in the south-west direction. The authors reconsidered the survey results obtained from a pollen analysis on the Oxygen Isotope Stage 5e, which was conducted in 1970, when almost a whole fossil of Palaeoloxodon naumanni was excavated in Churui, the Tokachi Plain, the eastern part of Hokkaido. The research has proven that the elephants lived in the period when the climate was warmer than now by 11 degrees or more Celsius and temperate deciduous broad-leaved forests prospered. Sedimentation in peat stratum in the Higashinopporo Wetland began in mean 5917±46 calBP, 1σ (NUTA2-27702), which nearly corresponded to the height of Holocene glacial retreat period, around 6,000 years ago. 石狩平野の中央部にある野幌丘陵の東側、東野幌湿原で1997年に採取した10.2mコアは温帯性落葉広葉樹林の存在を示し、少量のブナ花粉が連続出現していた。この地域には植栽され大木になったブナ親木集団が三つあり、その周りの東西7km、南北6kmの範囲内に2020年に設定した調査地点30カ所で表土を採取し花粉分析した。ブナ大木の樹冠下方では20%近い出現率でブナ落下花粉が存在したが。南~西方向へは0~1%の出現率であった。北海道東部の十勝平野の忠類で1970年にナウマンゾウ化石ほぼ1体分が発掘された時の酸素同位体ステージ5eの花粉分析を再考察した。現在より11ºC以上温暖な温帯性落葉広葉樹林植生が発達していた時代にこのゾウが生きていたことが判明した。東野幌湿原における泥炭層の堆積の始まりは縄文海進最盛期の6,000年前に近い5917±46calBPであった。 |
| Databáze: | OpenAIRE |
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