Hiraiga Fm Hn 0920b - Tanohata: Late Aptian, Japan
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Crinoidea
- Isocrinida
- Isocrinidae
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Bivalvia
- Carditida
- Astartidae
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Astarte (Trautscholdia) minor
Lea 1833
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Bivalvia
- Arcida
- Glycymerididae
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| see common names | |||||||
Geography
| Country: | Japan | State/province: | Iwate |
| Coordinates: | 40.1° North, 141.8° East (view map) | ||
| Paleocoordinates: | 48.3° North, 151.0° East (Wright 2013) | ||
| Basis of coordinate: | estimated from map | ||
| Geographic resolution: | outcrop |
Time
| Period: | Cretaceous | Epoch: | Early Cretaceous |
| 10 m.y. bin: | Cretaceous 2-3 | ||
| Key time interval: | Late Aptian | ||
| Age range of interval: | 119.57 - 113.2 m.y. ago |
Stratigraphy
| Geological group: | Miyako | Formation: | Hiraiga | ||
| Stratigraphic resolution: | bed | ||||
| Stratigraphy comments: Miyako group extends from Aptian - Albian. This collection comes from one of the uppermost Aptian formations in the group. This zone is reported to occur ~10m from the base of the Hiraiga Fm. This collection come from a few cm below collection Hn 920, which is the stratigraphically uppermost collection in the Hiraiga Fm. | |||||
Lithology and environment
| Primary lithology: | "cross stratification",fine lithified calcareous sandstone |
| Lithology description: calcareous, fine-grained, well washed (clean) sandstone with large scale cross stratification | |
| Environment: | foreshore |
| Geology comments: reported to be from high-energy, nearshore shallow water env. with clean, cross bedded sandstone. Most crinoid fossils are heavily disarticulated with rare, event derived articulated preservation | |
Taphonomy
| Modes of preservation: | body,original calcite |
| Size of fossils: | macrofossils |
| Preservation of anatomical detail: | variable |
| Abundance in sediment: | common |
Collection methods and comments
| Collection methods: | hydroflouric,field collection |
| Reason for describing collection: | taxonomic analysis |
| Taxonomic list comments:specimens appear to be stored at University Museum, University of Tokyo | |
Metadata
| Database number: | 65645 | ||
| Authorizer: | A. Miller | Enterer: | C. Ferguson |
| Modifier: | C. Ferguson | Research group: | marine invertebrate |
| Created: | 2006-09-23 17:23:14 | Last modified: | 2025-02-22 15:12:02 |
| Access level: | the public | Released: | 2006-09-23 17:23:14 |
| Creative Commons license: | CC0 |
Reference information
Primary reference:
| 18878. | T. Oji. 1985. Early Cretaceous Isocrinus from Northeast Japan. Palaeontology 28(4):629-642 [A. Miller/C. Ferguson] |