Reconstruction of paleo-environment in the Northwest Pacific during extreme greenhouse periods

2016 Fiscal Year Final Research Report

• Project/Area Number: 24244082
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Tohoku University
• Principal Investigator: Nishi Hiroshi 東北大学, 学術資源研究公開センター, 教授 (20192685)
• Co-Investigator(Kenkyū-buntansha): 高嶋 礼詩 東北大学, 学術資源研究公開センター, 准教授 (00374207) ; 山中 寿朗 岡山大学, 自然科学研究科, 准教授 (60343331) ; 桑原 義博 九州大学, 比較社会文化研究科(研究院), 准教授 (90281196)
• Research Collaborator: Selby David Durham University, Department of Earth Sciences, Professor
• Project Period (FY): 2012-04-01 – 2017-03-31
• Keywords: 白亜紀 / 温暖化 / 海洋無酸素事変 / 湿潤化 / 火成活動

Outline of Final Research Achievements

Mid-Cretaceous Oceanic Anoxic Events 2 and 1a are known as the extreme greenhouse climate periods. In order to understand paleo-environmental in the Northwest Pacific during OAE 2, 1a, we examined microfossil assemblage, carbon- and osmium isotope stratigraphy and clay mineral crystallinity of the OAE 2 and 1a intervals exposed in Japan. In the OAE 2 period, the emplacement of Large Igneous Provinces released large amounts of CO2 which induced a remarkable wet climate in the eastern margin of the Asian continent. Delivery of a large amount of nutrients from the land to the ocean caused elevation of primary productivity in the ocean surface, and resulted in depletion of oxygen in the ocean. The depletion oxygen continued relatively short period of time less than 100,000 years. On the other hand, in the OAE 1 a, anoxic environments in the ocean lasted over one million years in the Northeast Pacific.

Free Research Field

微古生物学