Japan Geoscience Union Meeting 2016

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Symbol S (Solid Earth Sciences) » S-SS Seismology

[S-SS31] Active faults and paleoseismology

Mon. May 23, 2016 9:00 AM - 10:30 AM IC (2F)

Convener:*Mamoru Koarai(Earth Science course, College of Science, Ibaraki University), Hisao Kondo(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Ken-ichi Yasue(Japan Atomic Energy Agency), Hideaki Goto(Graduate school of letters, Hiroshima University), Chair:Hideaki Goto(Graduate school of letters, Hiroshima University), Takashi AZUMA(National Institute of Advanced Industrial Science and Technology)

9:45 AM - 10:00 AM

[SSS31-04] Application of Dating Method by Free Iron Oxides Analysis for loess sediments (Red-Brown soil Layer) of Matsue Area, Japan

*Tanaka Masaaki1, Shohei Seiki1, Yuji Ito1, Yuichi Shimizu1, Takenobu Tanaka2 (1.The Chugoku Electric Power Co., Inc., 2.Hanshin consultants Co., Ltd.)

Keywords:Free iron oxides analysis, Crystallinity ratio, Soil age, Loess sediments, Red soil, Matsue area

As an alternative to soil dating method by using widespread tephras, it is proposed dating method based on free iron oxides analysis by Nagatsuka (1973).
In the Matsue area, tephras from Sanbe volcanoes (SK, about 105ka) and Daisen volcanoes (DMP, about 130ka) are preserved. In this study, the authors examined the applicability of dating method by free iron oxides analysis for loess sediments (Red-Brown soil layer) below the DMP.
As a result, loess sediments below the DMP is classified red soils by Nagatsuka (1973). Sasaki(2011) proved that it would take about 125ka for red soils to develop. The age is most consistent with tephra stratigraphy and chronology.
It shows that this method can be a good index of the degree of soil development.