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Volume 24 (1985 - 198･･･
- Issue 4 Pages 263-
- Issue 3 Pages 153-
- Issue 2 Pages 77-
- Issue 1 Pages 1-
Volume 24, Issue 4
Displaying 1-7 of 7 articles from this issue
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Toshio FUKUMA, Kazuo HUZITA1986 Volume 24 Issue 4 Pages 263-281
Published: January 31, 1986
Released on J-STAGE: August 21, 2009
JOURNAL FREE ACCESSThe Fukuchiyama Basin is one of the small intermontane basins distributed in the Meso-Paleozoic terrain of the northwestern part of the Kinki District. The basin is filled with the Quaternary deposits having wide sedimentary surfaces which are regarded as the extensions of the“Higher Terrace”widely spreading in the central part of the Kinki. The followings have been clarified by the present studies.
1) The Quaternary deposits in this basin reaches more than 50m in thickness consisting of five sedimentary units succeeded conformably, which are collectively called the Fukuchiyama Formation. Each unit was formed as a small fan developed along the marginal part of the basin or as fluvial deposit along the main river course flowing into the basin.
2) Fig. 13 is the summary of the results of the studies of the Fukuchiyama Formation from viewpoints of paint fossil and paleomagnetism. No evidence of the Metasequoia flora was found, which shows that this formation is correlative to the Upper Part of the Osaka Group. The Sabia bed, intercalated in the upper horizon of the formation, contains the plant remains of warmer or subtropical types and is thought to correspond to the Ma 8 horizon of the Osaka Group.
3) The paleomagnetic polarity of the Fukuchiyama Formation is normal except one narrow horizon showing reverse event. This is the character of the Brunhes Normal Epoch.
4) The Fukuchiyama Formation closely resembles to the Meimi Formation in the Harima Basin in various points, which has a FT age of 0.49±0.09 Ma in the lowest horizon.
5) The age of the Fukuchiyama Formation is inferred to be the Middle Pleistocene, about 0.6 or 0.7 Ma to 0.2 or 0.15 Ma, considering that the Brunhes Normal is generally dated 0.7 Ma to present with brief revesals at 0.11 and 0.02 Ma and Ma 8 horizon of the Osaka Group is intercalated with a volcanic ash layer having a FT ale of 0.38±0.04Ma.View full abstractDownload PDF (2948K) -
Akiko IWAUCHI, Yoshitaka HASE1986 Volume 24 Issue 4 Pages 283-293
Published: January 31, 1986
Released on J-STAGE: August 21, 2009
JOURNAL FREE ACCESSThe Asono Formation is a lacustrine deposit consisting of diatomaceous siltstone, tuffaceous sandstone, tuff and conglomerate. The formation abuts unconformably against volcanic basement rocks, including the Kumamureyama rhyolite that has a FT age of 0.73±0.14Ma. The upper part of the Asono Formation contains a lava flow which has a pseudo-pillow structure. This flow is called the Uchiyama hornblende andesite and its FT age is 0.34±0.17Ma. Thus the Asono Formation is inferred to deposit during the Middle Pleistocene.
The fossil diatoms from the Asono Formation are all freshwater species. Six zones have been identified, based on the predominant species.
Zone A: Cylotella zone
Zone B: Stephanodiscus zone
Zone C: Cyclotella zone
Zone D: Opephora zone
Zone E: Melosira zone
Zone F: Stephanodiscus zone
The fossil diatom assemblages show the water in Lake Asono was alkaline throughout deposition of the formation. The alkalinity was higher and the eutrophy more advanced during depostion of the Zone E and F sediments than the other sediments. Pollen analysis indicates probably cooler water temperature at the time of Zones B and F than the other zones.View full abstractDownload PDF (2836K) -
Toshiro NARUSE, Hitoshi SAKAI, Katsuhiro INOUE1986 Volume 24 Issue 4 Pages 295-300
Published: January 31, 1986
Released on J-STAGE: August 21, 2009
JOURNAL FREE ACCESSThe oxygen isotopic ratios of fine quartz from twenty Japanese soils developed in the last Glacial and Holocene ages are remarkably uniform (δ18O SMOW=14.1 to 16.9‰), suggesting their common origin in eolian dust; most Japanese soils have been influenced significantly by tropospheric eolian materials. The soils influenced by the eolian dust are enriched in the silt and clay fractions, especially in the top horizon of soils. Eolian silt and clay fractions have been gradually mixed with the weathered rock materials during the last Glacial age. The continuous addition of the eolian dust to the parent materials has also taken place during the Holocene age. The present findings of a widespread contribution of the eolian dust to the soil development also indicate that the Japanese Islands are situated on the fringe area of the semi-arid and arid Continent of Asia.
Eolian dust also originates in river beds (TAKESAKO and KATO, 1983) and coastal sand sheets. Consequently, it seems probable that the fine quartz has the multiple origins: from Chinese Continent and the above mentioned areas.
Further examination for the oxygen isotopic ratio of fine quartz should be carried out by comparing the value of the Chinese loess with those of the above mentioned two areas.View full abstractDownload PDF (772K) -
Ryotaro NOMURA, Shingo TANAKA1986 Volume 24 Issue 4 Pages 301-307
Published: January 31, 1986
Released on J-STAGE: August 21, 2009
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Kazuyoshi OKAMI, Mizuo MACHIDA, Mitsuru YOSHIDA1986 Volume 24 Issue 4 Pages 309-313
Published: January 31, 1986
Released on J-STAGE: August 21, 2009
JOURNAL FREE ACCESSDownload PDF (692K) -
Norio FUJI1986 Volume 24 Issue 4 Pages 315-318
Published: January 31, 1986
Released on J-STAGE: August 21, 2009
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1986 Volume 24 Issue 4 Pages e1
Published: 1986
Released on J-STAGE: August 21, 2009
JOURNAL FREE ACCESSDownload PDF (72K)
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