日本地球惑星科学連合2021年大会

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[J] ポスター発表

セッション記号 H (地球人間圏科学) » H-CG 地球人間圏科学複合領域・一般

[H-CG28] 堆積・侵食・地形発達プロセスから読み取る地球表層環境変動

2021年6月3日(木) 17:15 〜 18:30 Ch.09

コンビーナ:清家 弘治(産業技術総合研究所・地質調査総合センター)、池田 昌之(東京大学)、成瀬 元(京都大学大学院理学研究科)、高柳 栄子(東北大学大学院理学研究科地学専攻)

17:15 〜 18:30

[HCG28-P08] Linear stability analysis of plane beds with active suspended load

大畑 耕治1、*成瀬 元1、泉 典洋2 (1.京都大学大学院理学研究科、2.北海道大学工学研究院)

キーワード:ベッドフォーム、タービダイト、平坦床、デューン、安定性解析

Plane beds develop under riverine and marine environments and can be recorded as
parallel lamination in sandstone beds, such as those found in turbidites. However,
whereas turbidites typically exhibit parallel lamination, they rarely feature dunescale
cross lamination. Although the reason for the scarcity of dune-scale crosslamination
in turbidites is still debated, the formation of dunes may be dampened
by suspended load. Here, I perform linear stability analysis to show that flows
with suspended load facilitate the formation of plane beds. For a fine-grained bed,
suspended load can promote the formation of plane beds anddampen the formation
of dunes. These results of theoretical analysiswere verified with observational data
of plane beds under open-channel flows. In the case of coarse-grained beds, the
stability diagrams do not coincide with the experimental data of plane beds under
sheet flows. Further analytical studies of bedforms should consider sheet flows,
one of the transport modes associated with open-channel flows and sediment-laden
gravity currents.