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Volume 67 (2013)
- Issue 6 Pages 183-
- Issue 5 Pages 159-
- Issue 4 Pages 119-
- Issue 3 Pages 89-
- Issue 2 Pages 63-
- Issue 1 Pages 1-
Volume 67, Issue 5
Displaying 1-4 of 4 articles from this issue
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[in Japanese]Article type: Article
2013 Volume 67 Issue 5 Pages 159-
Published: September 25, 2013
Released on J-STAGE: May 12, 2017
JOURNAL OPEN ACCESSDownload PDF (7308K) -
[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...Article type: Article
2013 Volume 67 Issue 5 Pages 160-
Published: September 25, 2013
Released on J-STAGE: May 12, 2017
JOURNAL OPEN ACCESSDownload PDF (6692K) -
Masaki YUHARA, Hiroto OHIRA, Yoshinobu KAWANOArticle type: Article
2013 Volume 67 Issue 5 Pages 161-168
Published: September 25, 2013
Released on J-STAGE: May 12, 2017
JOURNAL OPEN ACCESSRuins of gold prospects occur within the Sawara Granite in the Gokayama district, located in the upper reaches of the Naka River. The granitoids around the gold prospects have been altered by hydrothermal activity. This hydrothermal alteration is characterized by the appearance of illite and pyrite. The maximum temperature of the alteration is estimated to be 230-280℃, based on previous fluid inclusion analysis. Fission track (FT) geochronological analysis was carried out to evaluate the cooling history of the granitic basement and the timing of the hydrothermal alteration. Zircon and apatite FT ages range from 83.1-62.0Ma and 18.2-3.8Ma, respectively. These FT ages and previous Rb-Sr data define a typical cooling history for the granitic basement in this area. A group of younger apatite FT ages (6.3-3.8Ma) from the alteration zone successfully indicates the hydrothermal activity in the Miocene to Pliocene period.View full abstractDownload PDF (769K) -
Kunio KAWAUCHI, Nobuyuki TAKAHASI, Seiichi YASUI, Hirotaka FUJISAKI, A ...Article type: Article
2013 Volume 67 Issue 5 Pages 169-180
Published: September 25, 2013
Released on J-STAGE: May 12, 2017
JOURNAL OPEN ACCESSCarbonized woods of such Pinaceae growing in taiga as Abies sachalinensis, Picea jezoensis, Picea glehnii and Larix gmelini are buried in the three horizons of the Kuttara pyroclastic deposits in the Satsunai plateau of Noboribetsu, southwest Hokkaido, Japan. The woods are named "Noboribetsu Petrified Forest", and chocolate-colored bands (paleosol bands) appear just beneath the three horizons. The 4th paleosol band is newly discovered in the area. The authors traced the paleosol bands beneath the Kt-1 and Kt-6 horizons stratigraphically over the area, then trenched for soil samples and observed in detail the paleosols in some typical outcrops. The results are summarized as follows: Paleosols are found in 4 horizons. The 1st and 3rd paleosol bands in descending order from the surface (1st is shallowest) are successively spread over the study area, the 2nd and 4th paleosol bands are locally observed. Carbonated woods are only found at the bottom of the Kt-1 and Kt-6 tephra horizons overlying the paleosol bands. In addition, the roots of carbonated trees are only found in the paleosol bands. The paleosol bands are composed of A, B and C or B and C soil horizons. The composition of the soil horizons alternates gradually between A,B,C and B,C in a horizontal direction. Diagenesis has substantially changed the initial characteristics of the paleosol bands following pyroclastic deposition. The authors expected that the paleosols would be transformed into podsolic soils in the area. But the authors couldn't find any clear evidence of this, such as albic horizons or accumulation horizons.View full abstractDownload PDF (1399K)
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