JpGU-AGU Joint Meeting 2017

講演情報

[EE]Evening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] [EE] デルタ(三角州):複雑系への学際的アプローチ

2017年5月24日(水) 17:15 〜 18:30 ポスター会場 (国際展示場 7ホール)

[HCG28-P07] 黄河デルタの堆積速度と堆積構造分布

ツオウ リャンヨン2リュウ ジャン2、*斎藤 文紀1,3ガオ マオシェン2ディアオ シャオボ2チュウ ジャンドン2ペイ シャオフェン2 (1.国立研究開発法人産業技術総合研究所地質情報研究部門、2.中国地質調査局青島海洋地質研究所、3.島根大学汽水域研究センター)

キーワード:Yellow River (Huanghe), sedimentation rate, delta lobe

Since 1976 the Yellow River channel has been located on the east side of delta complex and has built out a broad sedimentary lobe. In 2012, extensive bathymetric and high resolution seismic profiles, vibrocores in the survey lines and surface sediments were collected off the Yellow River delta and in Laizhou Bay. This study examines the sedimentation and morphology in the modern Yellow River delta and in Laizhou Bay, based on analyses of radionuclides (137Cs, 210Pb, 134Cs), sediment structure and texture, surface sediment distribution pattern, and the morphological change between 1976 and 2012. Bathymetric profiles, especially the S-N profiles, reveal the present morphology of the delta front which exceed previous estimated boundary, and this also validate on basis of analysis of 137Cs in cores. The 137Cs onset depths corresponding to the depths of lithological changes and morphological changes indicate that it can be a proxy to track the dispersal of Yellow River-derived sediments in the study area. Synthesis of bathymetry, seismic profiles, 137Cs profiles and surface sediment pattern show that a depocenter occurs in the south frank of the Yellow River delta (morphologically a spit) in west of Laizhou Bay. The deposition probably results from the headland eddy that formed with the morphological change. 210Pb profiles only in shelf area provide reliable accumulation rates, while 137Cs profiles show the depositional thickness in the whole area. Morphological changes along with 137Cs profiles of cores were used to establish the present sedimentary frame of the delta front slope and sediment dispersal in the west of Laizhou Bay.