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Volume 50 (1996)
- Issue 6 Pages 427-
- Issue 5 Pages 341-
- Issue 4 Pages 273-
- Issue 3 Pages 203-
- Issue 2 Pages 95-
- Issue 1 Pages 1-
Volume 50, Issue 6
Displaying 1-8 of 8 articles from this issue
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the first studied and valuable fossilsNoboru Yamashita, Hiroshi Miyajima, Ko TakenouchiArticle type: Article
1996 Volume 50 Issue 6 Pages 427-431
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSDownload PDF (2196K) -
Hideo Yabe, Masatoshi GotoArticle type: Article
1996 Volume 50 Issue 6 Pages 432-440
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSMany fossil elasmobranchs (sharks and rays) have been obtained from the Middle Miocene Iwadono Formation, Kuzubukuro, Higashi-Matsuyama City, Saitama Prefecture, Japan. Earlier work described 16 genera and 31 species of elasmobranchs, however, identification was incomplete. We have recently studied the teeth of Carcharocles (Elasmobranchii: Lamniformes) from this locality. Based on the teeth morphology, such as regularly serrated cutting edges and cusplets pair absent, most specimens (fifty-three) agree with C. megalodon. Nine specimens resemble upper lateral teeth of C. megalodon, but at the same time differ in other features, such as outer shape, mesial cutting edge, distal cutting edge, apex of the cusp and serrations. As it is difficult to distinguish variation within a species from the lateral teeth, therefore, we tentatively identify the present specimens as Carcharocles sp. It can be inferred from the teeth size that most of the Carcharocles species may have been large nektonic fishes. Hence, there is a high possibility that additional specimens could be found from other localities, and enable us to recognize whether the variation shown by the present specimens are within the genus or are a different species.View full abstractDownload PDF (1199K) -
Masahiro Shiba, Kazuhiro Sogo, Masanori Kawabe, Hiroshi Takeshima, Yas ...Article type: Article
1996 Volume 50 Issue 6 Pages 441-455
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSThe late Neogene series, the Sagara and the Kakegawa Groups, are distributed in. Shizuoka Prefecture, Central Japan. Although the stratigraphy and the biostratigraphy of these series have been studied by many workers as one of the standard Neogene type series on the Pacific coast of Japan, the stratigraphic boundary and relationships between the Sagara and the Kakegawa Groups may be still indistinct. The Sagara Group is divided into the Sugegaya Formation and the Oyori Formation in ascending order. The Sugegaya Formation is subdivided into the Tokigaya alternation of conglomerate and sandstone and the Sugegaya alternation. The Oyori Formation is composed with the Hirugaya alternation, the Oyori mudstone, the Takao conglomerate, the Sakaguchi conglomerate and the Kiriyama mudstone rich alternation. The Kakegawa Group is divided into the Katsuma Formation, the Hagima Formation and the Tanno Formation in ascending order. The Katsuma Formation is composed with the Katsuma conglomerate, the Kakigaya sandstone, the Katsuta mudstone rich alternation, the Araya sandstone and the Nakajima conglomerate. The Hagima Formation is subdivided into the Hagima sandstone rich alternation and the Arakawa mudstone rich alternation. The Tanno Formation is subdivided into the Kawakami sandstone rich alternation and the Isobe mudstone rich alternation. This study has revealed that the basal horizon of the Kakegawa Group is the base of the Nakajima conglomerate and the Katsuma conglomerate in Kiriyama-Katsuma area, the base of the Kakigaya sandstone in Hagima area and the base of the Hagima sandstone rich alternation in Niino area. The relationship between the Sagara and Kakegawa Groups is.thought to be unconformity in the northern area, because the basal horizon of the Kakegawa Group onlaps on the Sagara Group in the northern area and it downlaps in the southern area.View full abstractDownload PDF (2325K) -
Chihiro Miyakawa, Shusaku Yoshikawa, Zenko IkedaArticle type: Article
1996 Volume 50 Issue 6 Pages 456-465
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSTephrochronological study and detail lithological description were carried out on 260m drill core-sample, from the Port Island, Kobe City. Core-sample consist of intercalated between marine clay beds and fluviolacustrine silt, sand and gravel beds, deposited during the Middle to Late Pleistocene. On the basis of the stratigraphical and lithological data from core-sample in the Rokko Island and Koshienhama, Nishinomiya City, marine clay beds are correlated with Ma9 bed〜Ma13 bed. Besed on the volcaniclastic contens in the core sample, 8 volcanic ash layers and 8 ash-bearing horizons were identified. From the stratigraphic position and petrographic properties of individual volcanic ash, the 8 volcanic ash layers were correlated with some of ashes, described in the cores of the Lake Biwa and under the Osaka Plain. These are Yoko-oji (K-Ah), Heianjingu (Aira-Tn), Nanko-II (Aso-3), Koshienhama-III-VI, Koshienhama-I (BT51), Nishinomiya (Ata-Th) and Naruohama-III volcanic ashes. In the lower part and just below of the Ma9 bed, 2 thick volcanic ash layers were newly identified and were named as Minatojima-I and II.View full abstractDownload PDF (1423K) -
Relationship between genesis of melanic volcanic ash soils and human impactTakashi Sase, Mamoru HosonoArticle type: Article
1996 Volume 50 Issue 6 Pages 466-482
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSPhytolith analyses of the sequences of Holocene volcanic ash soils in Northeast Japan and North Island, New Zealand reveal the relationships between vegetation history and topsoil characteristics. Non-melanic topsoils occur under forest and melanic topsoils occur under grassland or fernland. In addition, it is recognized that shifts from non-melanic to melanic characteristics evident in the sequences took place as a result of changes in vegetation from forest to grassland or fern-land. The oldest change of this type in Northeast Japan occurred before c. 8.6 ka (age of the Nanbu Pumice), whereas the only change recognized in the New Zealand study area occurred more recently than c. 1.8 ka (age of the Taupo Pumice). This is consistent with Japan having a much longer human history, going back to the Pleistocene, than New Zealand, where human settlement dates from about 1,000 BP. The expansion of grassland, under which melanic characteristics develop, is considered to be the result of human-induced deforestation.View full abstractDownload PDF (2051K) -
Yasufumi Satoguchi, Shusaku Yoshikawa, Eiji Sasao, Yoshitaka NagahashiArticle type: Article
1996 Volume 50 Issue 6 Pages 483-500
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSThe Pliocene-Pleistocene Kakegawa Group in the Shizuoka Prefecture is composed of marine sediments. Many volcanic ash layers are intercalated in the upper part of the Kakegawa Group. In this study, 59 volcanic ash layers of the Upper Kakegawa Group are investigated to describe the lithofacies and petrographic properties. Some of these volcanic ash layers can be correlated with volcanic ash layers in the Tokai and the Kazusa Groups, based on their stratigraphic position, lithofacies and petrographic properties. The Arigaya I, Shiraiwa, Bounoya, Nishihirao volcanic ash layers of the Kakegawa Group are correlated with the Chomyoji II, Koyashiro, Otsujishinden, Bando 1 volcanic ash layers in the Tokai Group, respectively. The Kamihijikata I volcanic ash layer of the Kakegawa Group is correlated with the "Kd25" volcanic ash layer in the Kazusa Group.View full abstractDownload PDF (2774K) -
14C age of the Quaternary deposits in Japan (181)Kozo SendaArticle type: Article
1996 Volume 50 Issue 6 Pages 501-502
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSDownload PDF (281K) -
Article type: Appendix
1996 Volume 50 Issue 6 Pages 510-
Published: November 25, 1996
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSDownload PDF (69K)
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