Paleomagnetic Method Applied to a Suspected Deformed Sedimentary Layer Exposed at Oki Trench Site at the Agematsu Fault in Nagano Prefecture, Central Japan

DOI Web Site 1 Citations 12 References Open Access

Bibliographic Information

Other Title
  • 上松断層大木地区トレンチに出現した傾斜層の成因に関する古地磁気学的手法による検討
  • アゲマツ ダンソウ オオキ チク トレンチ ニ シュツゲンシタ ケイシャソウ ノ セイイン ニ カンスル コチジキガクテキ シュホウ ニ ヨル ケントウ

Search this article

Description

A paleomagnetic method was applied to decipher the origin of a dipping layer of the Agematsu fault at Oki trench sites (Si, S2). In S1 and S2 trenches, a sedimentary layer dipping up to 40 degrees was observed on the slope of bulge. It was discussed if the origin of dipping layer was due to tectonic deformation or to primary sedimentary structure. Oriented samples were collected from the same stratigraphic horizon. Alternating field (AF) demagnetization revealed that the remanent magnetization was divided into the stable primary component and the secondary component that could be cleaned by demagnetization at low AF levels. The primary component was estimated to be of DRM origin from low Qratio and high ARM/NRM ratio. The origin of dips of the sedimentary layer is considered to be primary sedimentary structure, because the scatter of the directions of remanent magnetization after the tilt correction is larger than that before the correction. There were large differences in the mean directions and the scatters of the secondary components between S1 and S2 trenches. In S2 trench, the secondary component showed less scatter than primary component and eastward deflection. The secondary component of S1 was regarded as VRM. There is a possibility that the origin of the secondary component in the S2 trench is due to lightning-induced remanent magnetization.

Journal

Citations (1)*help

See more

References(12)*help

See more

Related Projects

See more

Keywords

Details 詳細情報について

Report a problem

Back to top