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Volume 41 (1987)
- Issue 6 Pages 297-
- Issue 5 Pages 253-
- Issue 4 Pages 205-
- Issue 3 Pages 151-
- Issue 2 Pages 81-
- Issue 1 Pages 1-
Volume 41, Issue 3
Displaying 1-6 of 6 articles from this issue
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Keizo WATANABE, Kiyoaki NIIDAArticle type: Article
1987 Volume 41 Issue 3 Pages 151-164
Published: May 25, 1987
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSThe Late Jurassic Sarugawa Formation, which is composed of pillow lava, hyaloclastite, volcaniclastic conglomerate to mudstone and a small amount of chert, is widely exposed along the Nukabiragawa, Shudonigawa, and Shukushubetsugawa Rivers in the southern part of the Kamuikotan Belt. The Pillow lavas and hyaloclastites are petrographically classified into four types; 1) clinopyroxene-plagioclase phyric basalt, 2) aphyric basalt, 3) dolerite, and 4) aphyric trachyte. Considerable numbers of dykes are also observed in this area and are classified into three types; 5) amphibole-free dolerite, 6) kaersutite dolerite and 7) hornblende dolerite. Major elements of 15 representative rock samples were chemically analyzed. The pillow lavas of clinopyroxene-plagioclase phyric basalt, dolerite and aphyric trachyte and the dykes of kaersutite dolerite from the Shukushubetsugawa and the Nukabirgawa areas are characteristically alkaline, whereas the pillow lavas of aphyric basalt from the Shudonigawa-Osoushizawa area are tholeiitic. The hornblende dolerite dykes have a high FeO*/MgO ratio showing more evolved tholeiitic nature. Volcanic piles along the Shukushubetsugawa River and on the southern side of the Nukabiragawa River are considered to be detached slices of Jurassic seamounts and/or oceanic islands, taking the following geologic and petrologic aspects into account. 1) lithologic constitution of the volcanic piles are comparable to that of the present seamounts and oceanic islands. 2) Basaltic to trachytic pillow lavas and dykes have petrochemically alkalic nature. 3) Highly vesiculated pillow lavas and a large amount of hyaloclastites suggest submarine eruptions at a shallow level. 4) Structural features of the volcanic piles are similar to those from foot of submarine volcanic body. The pillow lavas and dykes of tholeiitic basalt and dolerite were probably derived from a Jurassic ocean floor. The petrochemical nature, however, is characterized by high FeO*/MgO ratios and high MnO contents and low TiO2 contents, which are slightly different from those of mid-oceanic ridge basalts.View full abstractDownload PDF (2266K) -
Niigata University Research Group of Geology in Higashikubiki DistrictArticle type: Article
1987 Volume 41 Issue 3 Pages 165-181
Published: May 25, 1987
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSThe Mio-Pliocene is widely distributed in the Higashikubiki district of Niigata Prefecture, which is located in the northernmost area of the Fossa Magna. The Mio-Pliocene, attaining to more than 3,000 meters in total thickness, is lithologically divided into seven formations, that is, the Matsunoyama, Taruda, Sugawa, Tamugikawa, Shobu, Higashikawa, and Naradate formations. Each of them is mainly composed of the lithofacies as follows respectively, that is, the Matsunoyama Formation is of alternating beds of dacitic tuff breccia and tuff with dark grey mudstone, the Taruda Formation of alternating beds of sandstone and mudstone rich in mudstone, the Sugawa and Shobu formations of massive mudstone, the Tamugikawa Formation of alternating beds of sandstone and mudstone, and thick-bedded sandstone, the Higashikawa Formation of sandy siltstone, and the Naradate Formation of alternating beds of conglomerate, sandstone, and siltstone with volcanic rocks in the top. They have generally the conformable relationship each other. The tephra marker beds show the flysch-type alternation of the Tamugikawa Formation changes laterally into mudstone of the upper part of the Sugawa Formation and the Shobu Formation. From F. T. ages of volcanic tuff layers and foraminifera data, each formation is correlative with the Neogene strato-type of the Niigata sedimentary basin as follows, that is, the Matsunoyama and Taruda formations with the Upper Miocene Teradomari Formation, the Sugawa Formation with the Upper Miocene Shiiya Formation, the Tamugigawa Formation with the Lower Pliocene Hamatsuda Formation, the Shobu and Higashikawa formations with the lower part of the Plio-Pleistocene Nishiyama Formation, and Naradate Formation with the Lower-most and Lower Formation of the Plio-Pleistocene Uonuma Group. It is considered that the sedimentary environment changed as follows, that is, from the lower bathyal basin plain in the Late Miocene, through the upper bathyal trough and slope in the Early Pliocene and the littoral shelf in the Middle Pliocene, to the neritic and partial terrestrial environment in the Late Pliocene. The change in the movement of sedimentary basin took place in earliest Pliocene age.View full abstractDownload PDF (2510K) -
Toshiyuki TANAKA, Akio HARA, Toshiyuki OHBA, Kazuo KIMINAMIArticle type: Article
1987 Volume 41 Issue 3 Pages 182-187
Published: May 25, 1987
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSDownload PDF (689K) -
Iburi Collaborative Research GroupArticle type: Article
1987 Volume 41 Issue 3 Pages 188-193
Published: May 25, 1987
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSDownload PDF (764K) -
Makoto MUSASHINO, Shigemi KIRIMURA, Hiroaki ISHIGAArticle type: Article
1987 Volume 41 Issue 3 Pages 194-197
Published: May 25, 1987
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSDownload PDF (1350K) -
14C age of the Quaternary deposits in Japan (164)Toshiro NARUSE, Katsuhiro INOUEArticle type: Article
1987 Volume 41 Issue 3 Pages 198-201
Published: May 25, 1987
Released on J-STAGE: June 06, 2017
JOURNAL OPEN ACCESSDownload PDF (422K)
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