Evaluation of impacts by sea-level rise on the alluvial deltas

在此基础上，对位于新泻平原西部的约罗伊加塔130m钻孔的冲积沉积物进行了沉积相和生物相分析，确定了54个样品的年龄，恢复了末次冰期后切割谷地的埋藏过程和海平面上升的沉积过程。现海区近万年来的沉降率约为3 mm/年。在Agano Rives Niigata河口测量了咸水入侵的变化，包括枯水期和丰水期流量的波动、咸水和淡水的水质以及水体和底层沉积物中沉积物的沉积学和化学特征。在枯水期，咸水从河口12公里处达到。盐跃层通过回声测深系统揭示出弱混合型咸水/淡水分界线的咸水楔体。为FI-…的运动和安放提供了重要的基础数据在越南南部湄公河三角洲的Tra Vinh省巴登海岸，在旱季和雨季，从地貌和沉积学的角度研究了近岸沙洲和沙滩的兴衰。在侵蚀和沉积海岸，沿岸沙洲和海滩表面的地貌和沉积结构随着沿岸和波浪流向和速度的变化而发生变化。对湄公河支流CoChien Rive2000-2005年间测量的咸水入侵结果进行了总结和发表，并以扫描声纳的方式研究了2007年初大地震时新泻地区出云崎附近海底出现的大量老木材的赋存模式。结合木材海底赋存状态，对木材的~(14)C年龄和树种进行了综合分析，讨论了大量木质木材的形成和运移过程，为地层的详细考虑提供了基础数据。冲积三角洲和平原少的过程

Sedimentological facies and biofacies have been analyzed and ages of 54 samples have been dated for alluvial sediments of 130 m core bored at Yoroigata, located in the western part of Niigata Plain On the basis of the results, burial process of the incised valley and sedimentary process of the Niigata plain by sea-level rise after the last glacial age have been reconstructed. Depression rate of the present area is about 3 mm/year during last 10,000 years.Changes of salt water intrusion as fluctuation of water discharge in low flow and high flow seasons, water quality of salt and fresh water; and sedimentological and chemical features of sediments in water masses and bottom sediments have been measured at the river mouth of Agano Rives Niigata. In the low flow season, salt water reached at 12 km from river mouth. Halocline by echo-sounding system revealed salt water wedge of weak-mixed type of salt/fresh water boundary. The important basic data has been get for movement and settle of fi … More ne-grained sediments.Prosperity and decline of longshore bars and sand beaches have been investigated geomorphologically and sedimentologically during dry and wet seasons at the Badon coast, Tra Vinh Province, Mekong River delta, south Vietnam. Geomorphology and sedimentary structure of surface of longshore bars and beaches have been changed as changes of direction and speed of longshore and wave currents during dry and wet seasons at the erosional and depositional coasts.The result of salt water intrusion measured along Co Chien Rivet one tributary of the Mekong River from 2000 to 2005 were summarized and published as papers.Occurrence mode of a lot of old woods appeared on the sea bottom surface off Izumozaki, Chuetsu district, Niigata, at the time of 2007 Chuetsu-Oki Earthquake has been investigated by scanning sonar. The analysis of 14C ages and species of woods were synthesized with occurrence mode on the sea bottom of the woods, and a formation and transportation processes of a lot of Jomon woods were discussed.The result of present study supplied the basic data for the detail consideration of formation. process of alluvial delta and plain Less