Impacts of disasters and human activities on sedimentation in hemipelagic environment

2014 Fiscal Year Final Research Report

• Project/Area Number: 24650603
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geography
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: SHIRAI Masaaki 首都大学東京, 都市環境科学研究科, 准教授 (50359668)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 深海底 / 半遠洋環境 / 河川 / ダム堆積物 / 堆積物供給 / 東海沖 / 熊野沖 / 新潟沖

Outline of Final Research Achievements

Mass accumulation rate (MAR) of hemipelagic deep marine sediments during ca. 50 to 100 years off the Tokai, Kumano and Niigata, central Japan were estimated based on vertical change in Pb-210 radioactive concentration. Although turbidite mud was not distinguished from hemipelagic mud with concentration of Pb-210 radioactivity, decreases in the middle 20th century were observed from several core samples in each area. Estimated ages of the decrease in MAR agree well with age of huge dam construction. In addition, decrease in MAR was restricted in frontal area of a river mouth in the Niigata area. These facts suggest that human activity (huge dam construction and obstruction of sediment transport) impacts not only on coastal area but also hemipelagic deep marine.

Free Research Field

堆積学