The role of mantle for atmospheric transition from Archean to Proterozoic

2023 Fiscal Year Final Research Report

• Project/Area Number: 19KK0091
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 17:Earth and planetary science and related fields
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Yuichiro Ueno 東京工業大学, 理学院, 教授 (90422542)
• Co-Investigator(Kenkyū-buntansha): 石川 晃 東京工業大学, 理学院, 准教授 (20524507) ; 青山 慎之介 横浜国立大学, 大学院環境情報研究院, 日本学術振興会特別研究員 (50814232) ; 青木 翔吾 秋田大学, 国際資源学研究科, 助教 (60801967)
• Project Period (FY): 2019-10-07 – 2024-03-31
• Keywords: GOE / コマチアイト / 硫黄同位体異常 / 白金族元素

Outline of Final Research Achievements

High-precision analysis of multiple sulfur isotope anomalies and platinum-group elements were performed on Archean and Proterozoic komatiites and granitoids. The results showed that sulfur components from subducted oceanic lithosphere were found in some Archean komatiites. Similar Archean seawater components were also found to be present in some granites. On the other hand, the HSE analysis of different ages of komatiites showed that igneous activity within the mantle increased at the end of the Archean. These results suggest that intense volcanism at around Archean/Proterozoic boundary may have significant role for the chemistry of Earth's surface environment.

Free Research Field

地球化学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は地球表層の酸化還元状態等の環境変動を解読するにあたってこれまで重視されてこなかった火成岩類の地球化学的分析が有用であることを示したものである。高精度の多種硫黄同位体と共振鉄製元素の分析を用いて、地殻物質のリサイクル、太古代マグマ成因論、およびマントルの化学組成特に酸化還元進化とその表層環境への影響を評価するための新たな方法論を提示した学術的意義がある。