Secular change of CO2 levels in the atmosphere and ocean through the Earth history

2016 Fiscal Year Final Research Report

• Project/Area Number: 25707038
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Geology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: SHIBUYA Takazo 国立研究開発法人海洋研究開発機構, 深海・地殻内生物圏研究分野, 研究員 (00512906)
• Research Collaborator: SAITO Takuya 東京工業大学, 地球生命研究所, 研究員 (50760617)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 地球史 / 流体包有物 / 大気 / 海洋 / 二酸化炭素

Outline of Final Research Achievements

To reconstruct the secular change of CO2 levels in the atmosphere and ocean through the Earth history, we analyzed fluid inclusions retained in hydrothermal quartz deposits that precipitated within open spaces of oceanic pillow lavas from 12 areas with 9 ages in the world. As a result, we revealed that sufficient greenhouse effect was maintained by the atmospheric CO2 to compensate the faint young sun in the early to middle Archean and that CO2 levels in the atmosphere and ocean drastically decreased from the late Archean to the early Proterozoic. These results suggest that the decrease in CO2 levels in the atmosphere and ocean was caused by the first appearance of the supercontinent and its breakdown and that the drastic drawdown of CO2 levels lasted until 2.2 Ga and likely triggered the global glaciation.

Free Research Field

地質学、地球化学