Puale Bay ammonoids, Level 25: Semicostatum, Alaska
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Cephalopoda
- Ammonitida
- Arietitidae
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Arnioceras sp.
Hyatt 1867
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| see common names | |||||||
Geography
| Country: | United States | State/province: | Alaska |
| Coordinates: | 57.7° North, 155.4° West (view map) | ||
| Paleocoordinates: | 47.2° North, 92.5° West (Wright 2013) | ||
| Basis of coordinate: | estimated from map | ||
| Altitude: | 1 meters | ||
| Geographic resolution: | small collection |
Time
| Period: | Jurassic | Epoch: | Early Jurassic |
| Stage: | Sinemurian | 10 m.y. bin: | Jurassic 1 |
| Key time interval: | Semicostatum | Ammonoid zone: | Arnouldi |
| Age range of interval: | 199.5 - 192.9 m.y. ago |
Stratigraphy
Lithology and environment
| Primary lithology: | lithified calcareous siltstone | ||
| Includes fossils? | Y | ||
| Environment: | deep subtidal shelf | Tectonic setting: | back-arc basin |
Taphonomy
| Modes of preservation: | body,mold/impression |
| Size of fossils: | macrofossils |
| Abundance in sediment: | few |
Collection methods and comments
| Collection methods: | surface (in situ),field collection |
| Reason for describing collection: | biostratigraphic analysis |
Metadata
| Database number: | 68733 | ||
| Authorizer: | J. Pálfy | Enterer: | M. Bosnakoff |
| Modifier: | M. Clapham | Research group: | marine invertebrate |
| Created: | 2007-02-05 03:13:20 | Last modified: | 2025-02-22 15:12:02 |
| Access level: | the public | Released: | 2007-02-05 03:13:20 |
| Creative Commons license: | CC0 |
Reference information
Primary reference:
| 19807. | J. Pálfy, P. L. Smith, J.K. Mortensen and R.M. Friedman. 1999. Integrated ammonite biochronology and U-Pb geochronometry from a basal Jurassic section in Alaska. Geological Society America Bulletin 111(10):1537-1549 [J. Pálfy/M. Bosnakoff] |