Yubari Formation, Ishikari Group: Lutetian, Japan
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Bivalvia
- Unionida
- Margaritiferidae
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Margaritifera ? otatumei
Suzuki 1942
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Margaritifera perdahurica
(Yokoyama 1932)
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Bivalvia
- Venerida
- Corbiculidae
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unclassified
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| see common names | |||||||
Geography
| Country: | Japan |
| Coordinates: | 43.5° North, 142.0° East (view map) |
| Paleocoordinates: | 52.1° North, 134.7° East (Wright 2013) |
| Basis of coordinate: | based on nearby landmark |
| Geographic resolution: | local area |
Time
| Period: | Paleogene | Epoch: | Eocene |
| Stage: | Lutetian | 10 m.y. bin: | Cenozoic 2 |
| Key time interval: | Lutetian | ||
| Age range of interval: | 48.07 - 41.03 m.y. ago |
Stratigraphy
| Geological group: | Ishikari | Formation: | Yubari | ||
| Stratigraphic resolution: | formation | ||||
| Stratigraphy comments: STRATIGRAPHIC RELATIONS: From Yubari Fm, which overlies the Horokabetsu and underlies the Wakkanabe Fm, all of the Ishikari Gp (early Middle Eocene). THICKNESS: From unit which reaches a thickness of 100-250 m. AGE: early Middle Eocene according to Takano and Waseda (2003). Referred only to Eocene in Mizuno (1964). STRATIGRAPHIC POSITION: Composite checklist for formation from local area. | |||||
Lithology and environment
| Primary lithology: | lithified siltstone |
| Lithology description: SPECIFIC LITHOLOGY: Sandstone and siltstone. LITHIFICATION: Assume to be lithified on the basis of age and photgraphic plates of Takano and Osamu (2003). | |
| Environment: | fluvial indet. |
| Geology comments: ENVIRONMENT: Contains freshwater shells. | |
Taphonomy
| Modes of preservation: | body,cast,mold/impression |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection methods: | field collection |
| Reason for describing collection: | taxonomic analysis |
| Collection method comments: COLLECTOR: T. Mizuno (c. 1960's). REPOSITORY: Unknown, not stated in text. | |
| Taxonomic list comments:COVERAGE: Exhaustive for bivalvia and gastropoda. NOMENCLATURE: Somewhat antiquated, but with species-level identifications. | |
Metadata
| Database number: | 70899 | ||
| Authorizer: | A. Hendy | Enterer: | A. Hendy |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 2007-04-11 08:27:43 | Last modified: | 2025-02-22 15:12:02 |
| Access level: | authorizer only | Released: | 2008-04-11 08:27:43 |
| Creative Commons license: | CC0 |
Reference information
Primary reference:
| 23771. | A. Mizuno. 1964. Summary of the Paleogene molluscan faunas in North Japan. Geological Survey of Japan Report 207 [A. Hendy/A. Hendy/A. Hendy] |