Hiraiso Fm. in the Hiraiso Coast, Facies Ha: Spathian, Japan
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Crinoidea
- Holocrinida
- Holocrinidae
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Holocrinus sp.
Wachsmuth and Springer 1886
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common category | |||||||||
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Bivalvia
- Pectinida
- Aviculopectinidae
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| very common category | ||||||||||
| (13 measurements) | ||||||||||
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Bivalvia
- Pectinida
- Entoliidae
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| common category | ||||||||||
| (2 measurements) | ||||||||||
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Bivalvia
- Ostreida
- Bakevelliidae
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| common category | ||||||||||
| (3 measurements) | ||||||||||
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Bivalvia
- Cardiida
- Anthracosiidae
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Unionites aff. canalensis
(Catullo 1847)
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| questionable; U. aff. canalensis var. fassaenis (1 measurement) | ||||||||||
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Bivalvia
- Trigoniida
- Myophoriidae
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Neoschizodus cf. laevigatus
(Ziethen 1830)
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common category | |||||||||
| (4 measurements) | ||||||||||
| see common names | ||||||||||
Geography
| Country: | Japan | State/province: | Miyagi |
| Coordinates: | 38.8° North, 141.5° East (view map) | ||
| Paleocoordinates: | 4.9° North, 138.8° East (Wright 2013) | ||
| Basis of coordinate: | estimated from map | ||
| Geographic resolution: | outcrop |
Time
| Period: | Triassic | Epoch: | Early Triassic |
| Stage: | Olenekian | 10 m.y. bin: | Triassic 1 |
| Key time interval: | Spathian | ||
| Age range of interval: | 248.6 - 247 m.y. ago |
Stratigraphy
| Formation: | Hiraiso | ||||
| Stratigraphic resolution: | group of beds | ||||
| Stratigraphy comments: Bando (1970) originally assigned the Hiraiso Fm. to the Griesbachian, later it was assigned to the Smithian by Nakazawa et al. (1994). Reidentification of Bando's ammonite as Neocolumbites and discovery of Tirolites in the lower part of the formation suggests a Spathian age for the Hiraiso Formation (Shigeta & Nakajima, 2017). Listed fossils belong to the Facies Ha, one of nine identified facies in the Hiraiso Fm. | |||||
Lithology and environment
| Primary lithology: | hummocky CS lithified sandstone |
| Lithology description: Thick hummocky-laminated sandstones with basal shelly deposits (amalgamated HCS). | |
| Environment: | offshore |
| Geology comments: Upper inner shelf. | |
Taphonomy
| Modes of preservation: | cast,mold/impression |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection methods: | field collection |
| Reason for describing collection: | paleoecologic analysis |
Metadata
| Database number: | 50116 | ||
| Authorizer: | W. Kiessling | Enterer: | S. Nurnberg |
| Modifier: | M. Clapham | Research group: | marine invertebrate |
| Created: | 2005-05-09 00:01:31 | Last modified: | 2025-02-22 15:12:02 |
| Access level: | the public | Released: | 2005-05-09 00:01:31 |
| Creative Commons license: | CC0 |
Reference information
Primary reference:
| 13473. | Y. Kashiyama and T. Oji. 2004. Low-diversity shallow marine benthic fauna from the Smithian of northeast Japan: paleocologic and paleobiogeographic imlications. Paleontological Research 8(3):199-218 [W. Kiessling/S. Nurnberg/S. Nurnberg] |