Paleomagnetic Evidence for Pleistocene Clockwise Rotation in the Oiso Hills: A Possible Record of Interaction Between the Philippine Sea Plate and Northeast Japan

  1. John W. Hillhouse
  1. Masato Koyama and
  2. Hiroshi Kitazato

Published Online: 18 MAR 2013

DOI: 10.1029/GM050p0249

Deep Structure and Past Kinematics of Accreted Terranes

Deep Structure and Past Kinematics of Accreted Terranes

How to Cite

Koyama, M. and Kitazato, H. (1989) Paleomagnetic Evidence for Pleistocene Clockwise Rotation in the Oiso Hills: A Possible Record of Interaction Between the Philippine Sea Plate and Northeast Japan, in Deep Structure and Past Kinematics of Accreted Terranes (ed J. W. Hillhouse), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM050p0249

Author Information

  1. Institute of Geosciences, Shizuoka University, Oya, Shizuoka 422, Japan

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875904542

Online ISBN: 9781118666609

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Keywords:

  • Geology, Structural—Congresses;
  • Geodynamics—Congresses;
  • Earth—Crust—Congresses

Summary

A Paleomagnetic study was made on the Pleistocene strata in the Oiso Hills located along the boundary between the Philippine Sea plate and the northeast Japan arc. This study evaluates the sense and amount of the Quaternary deformation associated with the interaction between the plates. About 170 sedimentary rock samples ranging in age from 0.2 to 1.0 Ma were measured. We used alternating field and thermal demagnetization to examine the stability of the natural remanent magnetizations. The mean field directions from the Numashiro, the Ninomiya, and the Haneo Formations, which range in age from 0.2 to 0.7 Ma, are nearly aligned with the present axial geocentric dipole field. In contrast, the directions from the Maekawa Formation. which ranges in age from 0.8 to 1.0 Ma, show on average 50° clockwise deflections of declination. These deflections are probably caused by clockwise tectonic rotation between 0.6 and 0.9 Ma. We propose and discuss three models of the rotation mechanism, (1) local drag along a major strike-slip fault, (2) regional dextral shear along the plate boundary, and (3) oroclinal bending caused by collision of a buoyant terrane.