Decoding early time formation history of the Japanese Islands using evidences in pre-Triassic geologic belts

2016 Fiscal Year Final Research Report

• Project/Area Number: 26400494
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: National Museum of Nature and Science, Tokyo
• Principal Investigator: Tsutsumi Yukiyasu 独立行政法人国立科学博物館, 地学研究部, 研究主幹 (00370990)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 砕屑性ジルコン / 年代 / 日本列島 / 古生代 / 後背地 / 大陸衝突 / 片麻岩

Outline of Final Research Achievements

Before the opening of the Sea of Japan in Miocene, the Japanese Island had been created at eastern Asian continental margin. Before Triassic, however, Eastern Asia was segmented for three blocks; North China, South China and Bureya cratons, and pre-Triassic sediments in Japan, the Kurosegawa, Hida Gaien, South Kitakami and Maizuru belts, were thought to attribute whichever. In this study, I try to get systematic detrital zircon data from them to reveal their attribution.
The Maizuru belt which thought to be settled near the boundary of the three continental blocks mentioned above, has complicated provenance history, which was caused by corrosion of the continental blocks. In contrast, the Kurosegawa belt is thought to be the fore-arc sediments because the provenance transition was poor. On the other hand, zircon dating of minor existence of gneissose rocks which occur in western foothill of Mt. Daisen show that the gneissose rocks were fragment of Jurassic high-T type metamorphic belt.

Free Research Field

地球年代学