Geological constraints on the formation of ferromanganese micronodules and the deep-sea environment

2017 Fiscal Year Final Research Report

• Project/Area Number: 16H07029
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Geology
• Research Institution: Forest Research and Management Organization
• Principal Investigator: Manaka Takuya 国立研究開発法人森林研究・整備機構, 森林総合研究所, 任期付研究員 (00784703)
• Project Period (FY): 2016-08-26 – 2018-03-31
• Keywords: マンガン団塊 / マイクロマンガンノジュール / 地質学 / 海底資源 / 深海環境 / 環境変動 / 地球化学 / 海洋科学

Outline of Final Research Achievements

In order to determine formation processes of ferromanganese macronodules and the deep-sea environment, I focused on micronodules in the deep-sea sediments in the North Pacific Ocean. I observed internal structure of the micronodules by making petrographic thin sections and using a micro-CT scanner, and found a low-density nuclei, which was coated with thin layers of high-density Fe-Mn oxides. High Mn/Fe ratios in the majority of the micronodules should be due to the relatively reductive condition of the surrounding seawater, when the micronodules were formed.

Free Research Field

生物地球化学