Reconstruction of intraoceanic subduction and paleogeography of oceanic plates in NW Pacific since late Mesozoic

2017 Fiscal Year Final Research Report

• Project/Area Number: 26400482
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: Niigata University
• Principal Investigator: Ueda Hayato 新潟大学, 自然科学系, 准教授 (70374197)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 海洋プレート古地理 / 海洋性島弧

Outline of Final Research Achievements

Because oceanic plates are subducted into the Earth interior within 200 m.y. since their birth, oceanic rocks incorporated in accretionary and ophiolitic terranes exposed on land play important roles on reconstruction of ancient oceanic plate configuration. This study examined petrology, stratigraphy, and geochronology of Mesozoic accretionary complexes and ophiolites in Hokkaido. The obtained data suggested existence of intraoceanic arc-trench systems independent from Eurasian active continental margin in the Mesozoic NE Pacific. It is probable that Japanese Islands developed under interactions between at least four tectonic plates in Jurassic to Cretaceous periods.

Free Research Field

地質学