Mokawaruppu River: Late/Upper Maastrichtian, Japan
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Cephalopoda
- Ammonitida
- Diplomoceratidae
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Diplomoceras cylindraceum
(Defrance 1816)
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see common names |
Geography
Country: | Japan |
Coordinates: | 43.1° North, 143.7° East (view map) |
Paleocoordinates: | 47.3° North, 133.0° East |
Basis of coordinate: | estimated from map |
Geographic resolution: | outcrop |
Time
Period: | Cretaceous | Epoch: | Late/Upper Cretaceous |
Stage: | Maastrichtian | 10 m.y. bin: | Cretaceous 8 |
Key time interval: | Late/Upper Maastrichtian | Foram zone: | Abathomphalus mayaroensis |
Age range of interval: | 72.10000 - 66.00000 m.y. ago |
Stratigraphy
Formation: | Kawaruppu | ||||
Stratigraphic resolution: | bed | ||||
Stratigraphy comments: Diplomoceras cylindraceum, reported here, was extracted from a siltstone 15 m below the K/Pg boundary. Magnetostratigraphy at this site indicates that the base of C30r is situated 45 m below the K/Pg boundary (Hamano et al., 1986; Hamano, 1988; Kaiho, 1992). Using the time scale of Ogg (2012) for the geomagnetical polarity and Vandenberghe et al. (2012) for the K/Pg boundary, the age of the base of C30r is 68.369 Ma, and the age of the K/Pg boundary is 66.0 Ma. Supposing that the sediment accumulation rate is constant based on the monotonous siltstone throughout the sequence, the age of the fossil horizon is estimated to be ~66.8 Ma. D. cylindraceum, therefore, lived to at least ~0.8 m.y. before the K/Pg boundary event in the north Pacific region. |
Lithology and environment
Primary lithology: | lithified siltstone |
Environment: | marine indet. |
Taphonomy
Modes of preservation: | body |
Size of fossils: | macrofossils |
Collection methods and comments
Reason for describing collection: | taxonomic analysis |
Collection method comments: Repository: Historical Museum of Urahoro, Hokkaido, Japan |
Metadata
Database number: | 177752 | ||
Authorizer: | M. Clapham | Enterer: | M. Clapham | Research group: | marine invertebrate |
Created: | 2016-04-09 22:57:58 | Last modified: | 2016-04-09 22:57:58 |
Access level: | the public | Released: | 2016-04-09 22:57:58 |
Creative Commons license: | CC BY |
Reference information
Primary reference:
58825. | K. Kurihara, M. Kano, H. Sawamura and Y. Sato. 2016. The last surviving ammonoid at the end of the Cretaceous in the north Pacific region. Paleontological Research 20:116-120 [M. Clapham/M. Clapham] |