Crustal rotation and unconformity in central Honshu caused by collision of the Izu-Bonin arc

2016 Fiscal Year Final Research Report

• Project/Area Number: 26400488
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: Aichi University of Education
• Principal Investigator: HOSHI Hiroyuki 愛知教育大学, 教育学部, 准教授 (90293737)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 地質学 / テクトニクス / 島弧衝突 / 回転運動 / 古地磁気 / 岩石磁気

Outline of Final Research Achievements

The geology and paleomagnetism of Miocene sediments on the Kanto Mountains (KM) were investigated in order to study the temporal relationship between crustal rotation and 15-Ma unconformity in central Honshu caused by collision of the Izu-Bonin arc. Results show that the KM rotated more than 90° clockwise after 17 Ma. However, smaller (30-40°) clockwise deflection of paleomagnetic direction was observed in middle Miocene strata located above the unconformity. These observations indicate that the vertical movement of crust, which resulted in the 15-Ma formation of unconformity, was accompanied by ~50° clockwise rotation. Results also indicate little rotation during the period between 15 and 10 Ma and then ~30° clockwise rotation after 10 Ma.

Free Research Field

地質学，古地磁気学