Understanding the interrelationships between tectonic rotation, faulting, and subsidence during the opening of the Sea of Japan

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K14822
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17040:Solid earth sciences-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Hosoi Jun 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, 主任研究員 (50760196)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 日本海拡大 / 回転運動 / 層序 / 棚倉断層帯 / 背弧拡大 / 堆積盆

Outline of Final Research Achievements

I conducted geological surveys, paleomagnetic analysis, and U-Pb dating to elucidate the interrelationships between tectonic rotation, volcanism, subsidence, and faulting in the Tanakura Basin during the opening of the Sea of Japan. As a results, a counterclockwise rotation of about 30° of the Tanakura Basin is found,and a high-resolution chronostratigraphy of the Neogene strata of the Tanakura Basin is constructed. Based on this chronostratigraphy, it is clear that the Tanagura Basin experienced rapid tectonic subsidence and block rotation due to the movement of the Tanakura Fault Zone from about 17.2 Ma to 16.6 Ma.

Free Research Field

地質学

Academic Significance and Societal Importance of the Research Achievements

本研究成果は日本海拡大に伴った様々な事象を実証的に結びつけたものである．具体的には，日本海拡大に伴った棚倉断層帯の運動，堆積盆の形成～発達と回転運動を同時に引き起こしたことを発見した．日本海拡大は世界的に有名な背弧拡大イベントである．そのため本研究成果は，現世および過去の，世界各地の，様々な背弧拡大テクトニクスを検討する上で，世界的にも重要な成果であると考える．