Advance of paleo- and rock magnetism by unraveling roles of biogenic magnetite

2016 Fiscal Year Final Research Report

• Project/Area Number: 25287137
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: The University of Tokyo
• Principal Investigator: Yamazaki Toshitsugu 東京大学, 大気海洋研究所, 教授 (80344125)
• Co-Investigator(Kenkyū-buntansha): 山本 裕二 高知大学, 自然科学系, 准教授 (00452699) ; 横山 祐典 東京大学, 大気海洋研究所, 教授 (10359648) ; 七山 太 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, 上級主任研究員 (20357685)
• Research Collaborator: Sakuramoto Yukihiro 東京大学, 大気海洋研究所
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 岩石磁気学 / 生物源マグネタイト / 環境磁気学 / 海洋地質学 / 走磁性バクテリア

Outline of Final Research Achievements

It was revealed that biogenic magnetite abundantly occurs in oxic sediments, and is not limited within the oxic-anoxic transition zone in a sedimentary column. The abundance of bullet-shaped magnetofossils increases near the oxic-anoxic transition zone. Magnetofossils are useful for estimating paleoenvironments. Variations in relative abundance of biogenic and terrigenous magnetites contaminate estimations of relative geomagnetic paleointensity variations from sediments. Remanent magnetization lock-in depths vary among sediment cores, which may be controlled by differences in the distribution of biogenic magnetites within sedimentary columns.

Free Research Field

古地磁気・岩石磁気学