Evolution of the arc-trench system that assembled the Paleo-Mesozoic rocks of Japan: Insights from detrital-zircon-age spectra

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400484
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: University of Toyama
• Principal Investigator: Otoh Shigeru 富山大学, 大学院理工学研究部(理学), 教授 (60194221)
• Co-Investigator(Kenkyū-buntansha): Yamamoto Koshi 名古屋大学, 環境学研究科, 教授 (70183689) ; Orihashi Yuji 東京大学, 地震研究所, 助教 (70313046) ; Ishizaki Yasuo 富山大学, 大学院理工学研究部(理学), 准教授 (20272891)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 地史 / 後背地解析 / ウラン－鉛年代 / ジルコン / 日本列島 / 古生代 / 中生代 / テクトニクス

Outline of Final Research Achievements

Paleo-Mesozoic tectonic development of proto-Japan is discussed from detrital-zircon-age spectra and a review of the zircon age of igneous rocks in the world.
The Middle Paleozoic sandstone, having Meso- to Neoproterozoic zircons, was mostly deposited along a Gondwana margin. The Permian sandstone, having only coeval zircons, was likely deposited in an island-arc setting. Supply of Paleoproterozoic zircons from North China started in Late Permian-Middle Jurassic times. Thus, Gondwana-derived separate island arcs seem to have successively amalgamated to the North China margin.
The Lower Cretaceous of NE Japan contained certain amounts of coeval zircons. The Early Cretaceous igneous rocks are limited along the eastern coast of South China and in some extensional basins of Central Asia. Combining paleobiogeographic data, I interpret that these Lower Cretaceous beds were deposited along the South China coast, suggesting that the part of NE Asia moved relatively southward along the coast.

Free Research Field

地史学，構造地質学及びテクトニクス