1999 Fiscal Year Final Research Report Summary
Stratigraphical Study on the Pleistocene Omma Formation and Related Strata Distributed in the Hokuriku Province, Central Japan
| Project/Area Number |
09640555
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Kanazawa University |
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Principal Investigator |
TSUKAWAKI Shinji Kanazawa Univ., Dep. Civil Eng., Assoc. Prof., 工学部, 助教授 (00222133)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAYAMA Toshiaki Jumonji Women's College, Professor, 教授 (40004361)
KATO Michio Kanazawa University, Dep. Ear. Sci., Professor, 理学部, 教授 (10093741)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Omma Formation / Early Pleistocene / lithostratigraphy / Kanazawa City / Hokuriku Province / volcanic ash layer / geological structure / molluscan shell bed |
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| Research Abstract |
The research results on the lithostratigraphical study on the Pleistocene Omma Formation and the related strata distributed in the Hokuriku Province, central Japan are as followings :
1. The Omma Formation is distributed mainly in the eastern to northern parts of the Kanazawa City, Ishikawa Prefecture, and the western part of the Oyabe City and Fukumitsu town, Toyama Prefecture in the investigated areas.
2. The Omma Formation is divided lithologically into the lower member composed mainly of bluish-grey mudstone, muddy sandstones and sandy mudstones with intercalations of pyroclastic layer, the middle member consisting of bluish-grey fine-grained sandstones with intercalations of volcanic ash layer and molluscan shell bed, and the upper member composed of yellowish brown fine-grained sandstones through most part of the investigated areas.
3. More than 15 traceable volcanic ash layers are recognized in the lower and middle members of the Omma Formation. Since a certain number of them are traceable wholly in the investigated areas, they are effective to correlate within the formation among the distributed areas.
4. The Omma Formation unconformably covers such Mio-Pliocene strata as the Takakubo and Saikawa Formations in the investigated areas. On the other hand, it is conformably overlain by the Utatsuyama Formation, but interfingering relationships between the Omma and Utatsuyama Formations are recognized in part.
5. The Omma Formation distributed in the investigated area are folded in broad anticlines and synclines trending NNE-SSW in general. Existence of a major thrust fault trending N-S to NE - SW is inferred from the eastern marginal part of the Kanazawa area to the southwestern part of the Oyabe area through the northern marginal part of the Fukumitsu area, and the Miocene strata distributed on the southeast of the fault are thrust over the younger strata such as the Omma and Takakubo Formations on the northwest.
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