Ainoshima Island (facies 1): Rupelian, Japan
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
|
Chondrichthyes
- Carcharhiniformes
- Carcharhinidae
|
|||||||
|
Negaprion sp.
Whitley 1940
|
|||||||
|
Chondrichthyes
- Lamniformes
- Lamnidae
|
|||||||
|
Isurus sp.
Rafinesque 1810
|
|||||||
|
Chondrichthyes
- Lamniformes
- Cetorhinidae
|
|||||||
|
Cetorhinus sp.
de Blainville 1816
|
|||||||
| see common names | |||||||
Geography
| Country: | Japan |
| Coordinates: | 34.0° North, 130.8° East (view map) |
| Paleocoordinates: | 36.5° North, 127.6° East (Wright 2013) |
| Basis of coordinate: | based on nearby landmark |
| Geographic resolution: | local area |
Time
| Period: | Paleogene | Epoch: | Oligocene |
| Stage: | Rupelian | 10 m.y. bin: | Cenozoic 4 |
| Key time interval: | Rupelian | ||
| Age range of interval: | 33.9 - 27.3 m.y. ago |
Stratigraphy
| Geological group: | Ashiya | Formation: | Yamaga | ||
| Stratigraphic resolution: | group of beds | ||||
| Stratigraphy comments: The age of the Yamaga Formation in the Ashiya area was placed at 31.7±2.3 Ma (upper Lower Oligocene) based on fission track dating (Ozaki and Hamasaki, 1991). This was supported by further fission track dating and biostratigraphic studies conducted in the upper and lower formations (Tsuchi et al., 1987; Ozaki and Hamasaki, 1991; Okada, 1992). | |||||
Lithology and environment
| Primary lithology: | massive,bioturbation,very fine sandstone |
| Lithology description: This facies is characterized by well bioturbated and massive (unlaminated) very fine sandstone to siltstone that is occasionally interbedded with about 10 cm thick medium- to coarse-grained sandstone layers containing volcaniclastics and shell remains. | |
| Environment: | offshore |
| Geology comments: Abundant bioturbation indicates an only minor influence of storm wave on the substrate. Therefore, Facies 1 was likely deposited within an outer shelf environment. Autochthonous Turritella shells with barnacles indicate a stable environment with low sedimentation rates. | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Reason for describing collection: | paleoecologic analysis |
| Collection method comments: Repository: University Museum, The University of Tokyo (UMUT) | |
Metadata
| Database number: | 277774 | ||
| Authorizer: | M. Clapham | Enterer: | M. Clapham | Research group: | vertebrate |
| Created: | 2026-02-11 21:40:31 | Last modified: | 2026-02-11 21:40:31 |
| Access level: | the public | Released: | 0000-00-00 00:00:00 |
| Creative Commons license: |
Reference information
Primary reference:
| 94182. | T. Tomita and T. Oji. 2010. Habitat reconstruction of Oligocene elasmobranchs from Yamaga Formation, Ashiya Group, western Japan. Paleontological Research 14:69-80 [M. Clapham/M. Clapham] |