1990 Fiscal Year Final Research Report Summary
Comparative Study on the Lithological Succession and Fossil Fauna of the Upper Palaeozoics in the Kitakami, Abukuma and Hida Mountains
| Project/Area Number |
01540641
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Niigata University |
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Principal Investigator |
TAZAWA Jun-ichi College of General Education, Niigata University ; Professor, 教養部, 教授 (50108453)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUOKA Atsushi College of General Education, Niigata University ; Lecturer, 教養部, 講師 (00183947)
NIIKAWA Isao College of General Education, Niigata University ; Associate Professor, 教養部, 助教授 (50134903)
HASEGAWA Yoshiyuki College of General Education, Niigata University ; Professor, 教養部, 教授 (80018572)
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| Project Period (FY) |
1989 – 1990
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| Keywords | South Kitakami-Hida Gaien Terrain / North Kitakami-Mino Terrain / Abukuma-Hida Terrain / Palaeozoic brachiopods / Jurassic radiolarians / Sino-Korea Massif |
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| Research Abstract |
The following new data were obtained from the Palaeozoic and Mesozoic rocks in the Kitakami, Abukuma and Hida mountains.
1. The Sorayama Formation of Fukuji, Hida Mountains consists of Palaeozoic ophiolitic rocks and Mesozoic volcanic rocks.
2. A Silurian trilobite Encrinurus was discovered from the Yoshiki Formation in Fukuji, Hida Mountains.
3. An Early Carboniferous brachiopod Rotaia was collected from the Hikoroichi Formation of Hikoroichi in the southern Kitakami Mountains.
4. The geographical distribution of the brachiopod genus Choristites, which generally occur from the Nagaiwa Formation in the southern Kitakami Mountains, was summarized. And its palaeobiogeography was discussed.
5. The Middle Permian brachiopod faunas of the southern Kitakami and Hida mountains are characterized by the presence of both Boreal and Tethyan elements. These regions were probably being a continental shelf developed along the northern and eastern margins of the Sino-Korean block in the Middle Permian time.
6. Some Middle Jurassic radiolarians were discovered from the Magisawa Formation of Hiraiga in the northern Kitakami Mountains.
7. From the above data, it is concluded that the South Kitakami Terrain can be correlated with the Hida Gaien Terrain ; and the North Kitakami Terrain is comparable with the Mino terrain. Both of the Abukuma and Hida terranes, having Precambrian rocks, are regarded as the oldest terrains in Japan. Northeast Japan and Southwest Japan are essentially same one in geology, although the connection between them is now obscure by large scale faults, the Tanakura Tectonic Line and the Itoigawa-Shizuoka Tectonic Line.
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