EE1038, Aze, Okinoshima Island: Bartonian, Japan
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Cephalopoda
- Nautilida
- Aturiidae
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| see common names | |||||||
Geography
| Country: | Japan |
| Coordinates: | 32.7° North, 129.8° East (view map) |
| Paleocoordinates: | 37.6° North, 126.1° East (Wright 2013) |
| Basis of coordinate: | estimated from map |
| Geographic resolution: | small collection |
Time
| Period: | Paleogene | Epoch: | Eocene |
| Stage: | Bartonian | 10 m.y. bin: | Cenozoic 3 |
| Key time interval: | Bartonian | ||
| Age range of interval: | 41.03 - 37.71 m.y. ago |
Stratigraphy
| Formation: | Okinoshima | ||||
| Stratigraphic resolution: | bed | ||||
| Stratigraphy comments: Lower to middle part of the Okinoshima Formation. According to foraminiferal and molluscan biostratigraphy, the formation is assigned in age to the Auverisian to the Bartonian (Upper Eocene). The Okinoshima Formation falls within calcareous nannofossil Subzones CP14a–CP15b of Okada and Bukry (1980) and planktic foraminiferal Zones E10–E13 of Berggren and Pearson (2005), dating to the middle Eocene. The Okinoshima Formation including calcareous nannofossils such as Reticulofenestra umbilica and Discoaster barbadiensis, indicating Zones CP14–CP15 and planktic foraminifer, Acarinina primitiva, representing Zone P14 or older (Yamaguchi et al. 2004). These biozones of planktic microfossils assign the Okinoshima Formation to 43.5–39.0 Ma (Yamaguchi & Kamiya, 2007). | |||||
Lithology and environment
| Primary lithology: | fine,glauconitic lithified sandstone |
| Lithology description: Fine- to medium-grained glauconitic sandstone or sandy siltstone | |
| Environment: | offshore |
| Geology comments: The biofacies consists of samples from muddy sandstones, sandy mudstones, and mudstones, which represent bioturbation and include few sedimentary structures that indicate wave and tidal influences. The planktic/total foraminifer ratios (P/T ratios) from the Okinoshima Formation is less than 0.03, suggesting water depths shallower than about 100–150 m. The lithofacies, P/T ratios, and molluscan assemblages indicate shallow-marine environments with little to no influence by wave and tidal action. Hence, the biofacies correlates with outer-shelf environments under warm-water conditions. | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Reason for describing collection: | taxonomic analysis |
| Collection method comments: Repository: Department of Earth Sciences, Ehime University | |
Metadata
| Database number: | 179881 | ||
| Authorizer: | M. Clapham | Enterer: | M. Clapham |
| Modifier: | M. Clapham | Research group: | marine invertebrate |
| Created: | 2016-07-03 17:24:01 | Last modified: | 2025-02-22 15:12:02 |
| Access level: | the public | Released: | 2016-07-03 17:24:01 |
| Creative Commons license: | CC0 |
Reference information
Primary reference:
| 59677. | K. Tanabe and N. Chiba. 1983. A new species of Deltoidonautilus (Cephalopoda) from the upper Eocene of western Kyushu. Venus (Japanese Journal of Malacology) 42:248-258 [M. Clapham/M. Clapham] |