Earth history ocean floor section reconstruction project: Elucidation of environmental changes from Archean to Proterozoic

2017 Fiscal Year Final Research Report

• Project/Area Number: 26257211
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Geology
• Research Institution: Kyushu University
• Principal Investigator: Kiyokawa Shoichi 九州大学, 理学研究院, 准教授 (50335999)
• Co-Investigator(Kenkyū-buntansha): 山口 耕生 東邦大学, 理学部, 准教授 (00359209) ; 田中 亮吏 岡山大学, 惑星物質研究所, 准教授 (00379819) ; 堀江 憲路 国立極地研究所, 研究教育系, 助教 (00571093) ; 伊藤 孝 茨城大学, 教育学部, 助教授 (10272098) ; 後藤 孝介 国立研究開発法人産業技術総合研究所, 地質調査総合センター, 研究員 (30612171) ; 尾上 哲治 熊本大学, 大学院先端科学研究部(理), 准教授 (60404472) ; 菅沼 悠介 国立極地研究所, 研究教育系, 准教授 (70431898) ; 池原 実 高知大学, 教育研究部自然科学系理学部門, 教授 (90335919)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 太古代 / 原生代 / 海底環境 / 酸素濃度 / 掘削コア

Outline of Final Research Achievements

Understanding of the Archean - Proterozoic deepsea ocean environment, we pick up 4 location to understand sedimentary sequence of each other sequence. 3.1Ga Australia Pilbara, 2.3Ga Ghana Birimian greenstone belt. 1.8 Ga Trans Hadson orogeny at formation time of the north America. 0.7Ga Egypt greenstone which contains BIF within volcaniclastics.
We did Scientific drilling at GHB of Ghana. It successfully got 195 m long volcanosedimentary sequence. This Ghana age is very important to understand when oxidation occur and affected oceanic sediment. We do chemical analysis but machine time is so tight. This work is still on going. Based on the thin section work, each sedimentary sequence well preserved sedimentary environment, but Oxygen effect is still hardly understood at bottom of ocean. At the early Proterozoic time, Oxygen level is still very low, however, biogenic activity well identified several places.

Free Research Field

地質学