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Volume 55 (2001)
- Issue 6 Pages 321-
- Issue 5 Pages 263-
- Issue 4 Pages 197-
- Issue 3 Pages 129-
- Issue 2 Pages 69-
- Issue 1 Pages 1-
Volume 55, Issue 6
Displaying 1-5 of 5 articles from this issue
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Fujio Kumon, Takashi UmezawaArticle type: Article
2001 Volume 55 Issue 6 Pages 321-328
Published: November 25, 2001
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSThe Tetori Group outcropping along the Matsuyamadani in Shokawa Village, is divided into the Akahoke, Mitarai and Otanyama Formations in asccending order. Based on facies analysis, the Akahoke Formation with wave ripples and hummocky cross stratification, is considered to have been formed in inner continental shelf to shoreface associated with delta progradation. The Mitarai Formation yielding abundant marine fossils is outer continental shelf sediments in a maximum flooding phase. The Otaniyama Formation was deposited in shoreface to delta environments. A wide distribution of marine sediments was confirmed in the middle part of the Tetori Group. Belemnite fossils discovered in the lower part of Otaniyama Formation is also described briefly on its forms and occurrence.View full abstractDownload PDF (1507K) -
Kanji Shikano, Masahiro Kunimitsu, Masahiro SugiyamaArticle type: Article
2001 Volume 55 Issue 6 Pages 329-338
Published: November 25, 2001
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSThe Lower Cretaceous Itoshiro and Akaiwa subgroups of the Tetori Group are well cropped out along the upper reaches of the Oshirakawa River, Shirakawa Village. They are divided into the Hidagoe, Jigokudani, Kagidani, Kuwajima, Futamatadani, Okura and Akaiwa formations in ascending order. The dinosaur footprints were found on the surface of sandstone bed in the upper part of the Kagidani Formation. This was the first occurrence of dinosaur footprints in the northeastern part of Tetori province. There exist 36 concaves on a finegrained sandstone bed, and 17 among them are identified as dinosaur footprints. Straight-type current ripples are also well developed on the same bed surface, and the ripple marks are deformed by the footprints. Some tridactyl footprints recognized in the footprints are supposed to be imprinted by bipedal (ornithopods) dinosaurs. Many footprints indicate the migration from west to east, and several footprints form two trackways of same direction.View full abstractDownload PDF (3172K) -
Masahiro Yahata, Yaeko Igarashi, Minoru Tsukagoshi, Toshitsugu Maeda, ...Article type: Article
2001 Volume 55 Issue 6 Pages 339-356
Published: November 25, 2001
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSQuaternary sediments are widely distributed in the Sunagawa and Ishikari lowlands, the western margin of the Central Hokkaido, Japan. The stratigraphic setting and paleoenvironment of the Pleistocene terrestrial sediments in the Koshunai and Kurisawa districts in the southeastern area of the Sunagawa lowland are discussed based on the stratigraphy, fossil pollen and plant analysis, tephrochronology and 14C age determination. The Pleistocene sediments in the Koshunai district, consisting from clay, silt, sand and gravel associated with intercalation of peaty and tephra layers, are divided into the Aidanosawagawa, Koshunai and Higashiyama Formations in acending order. Each formation has an uncomformable relationship with underlying formation. Reconstructed vegetation and climate had changed from forest dominated with Picea and Tsuga under cool climate (Aidanosawagawa F.) to Picea dominated forest to Fagus-Juglans-Quercus forest under cool to temperate climate (Lower Member of Koshunai F.) to Larix and Picea domonated forest under cold climate (Upper Member of Koshunai F.) and to Picea dominated forest under cool climate (Higashiyama F.). The Aidanosawagawa Formation and the Lower Member of the Koshunai Formation may be correlated to the Lower-Middle Pleistocene Shimonopporo and Middle Pleistocene Otoebetsugawa Formarions respectively. The Lower Member of the Higashiyama Formation, intercalating the tephra layer (Toya; 90-100ka) of basal part, the member is correlated to the Upper Pleistocene Konopporo Formation in the Ishikari lowland. The Moseushi Formation in the Kurisawa district, ranging from ca. 45,000 y.B.P. to ca. 40,000 y.B.P. based on 14C age (44,980 y.B.P.) and pumice (Spfa 1) and pollen fossil (Tsuga-Abies mixed forest), is correlated to the upper part of the Lower and Upper Members of the Higashiyama Formation. Stratigraphy, gravel compositions and paleocurrent systems show that clastic were derived from the Ishikarigawa river in Early-Middle Pleistocene (Aidanosawagawa stage), whereas from the eastern mountain region in Middle-Late Pleistocene (Koshunai and Higashiyama Formations), resulting from the uplifting of the Yubari Mountains.View full abstractDownload PDF (2844K) -
Kana Ohta, Masahiko Akiyama, Norihisa Inuzuka, Kigen Arai, Toshio Naka ...Article type: Article
2001 Volume 55 Issue 6 Pages 357-360
Published: November 25, 2001
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSDownload PDF (914K) -
Shohachi NakamuraArticle type: Article
2001 Volume 55 Issue 6 Pages 361-365
Published: November 25, 2001
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSDownload PDF (931K)
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