Atsunai Formation - Kushiro coal field, eastern Hokkaido: Middle Miocene, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Bivalvia - Protobranchia - Sareptidae
Bivalvia - Protobranchia - Nuculanidae
Nuculanidae indet. Adams and Adams 1858
Bivalvia - Cardiida - Cardiidae
Bivalvia - Cardiida - Tellinidae
Bivalvia - Venerida - Veneridae
Bivalvia - Carditida - Carditidae
Cyclocardia sp. Conrad 1867
Bivalvia - Pectinida - Pectinidae
Mizuhopecten sp. Masuda 1963
Bivalvia - Ostreida - Ostreidae
Ostrea sp. Linnaeus 1758
Bivalvia - Arcida - Arcidae
Bivalvia - Arcida - Glycymerididae
Scaphopoda - Dentaliida - Dentaliidae
Gastropoda - Turbinidae
Homalopoma sp. Carpenter 1864
Gastropoda - Turritellidae
Turritella sp. Lamarck 1799
Gastropoda - Calyptraeidae
? Crepidula sp. Lamarck 1799
Gastropoda - Naticidae
Euspira sp. Agassiz 1837
Tectonatica sp. Sacco 1890
see common names

Geography
Country:Japan
Coordinates: 42.8° North, 143.8° East (view map)
Paleocoordinates:42.8° North, 141.0° East (Wright 2013)
Basis of coordinate:based on nearby landmark
Geographic resolution:local area
Time
Period: Neogene Epoch: Miocene
10 m.y. bin: Cenozoic 5
Key time interval: Middle Miocene
Age range of interval: 15.98 - 11.63 m.y. ago
Stratigraphy
Formation:Atsunai
Stratigraphic resolution:formation
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From Atsunai Fm of the Atsunai Gp, which overlies the Tokomuro Fm of the Ombetsu Gp (Late Oligocene) and is overlain by the Shiranuka Fm of the Atsunai Gp (Early Pliocene). THICKNESS: ~700 m thick. AGE: Middle Miocene on the basis of molluscan biostratigraphy. STRATIGRAPHIC POSITION: Composite checklist for formation.
Lithology and environment
Primary lithology: poorly lithified sandstone
Secondary lithology: poorly lithified siltstone
Includes fossils?Y
Includes fossils?Y
Lithology description: SPECIFIC LITHOLOGY: Sandstone, siltstone, tuff and conglomerate. LITHIFICATION: Assumed to be poorly-lithifed on the basis of age.
Environment:coastal indet.
Geology comments: ENVIRONMENT: Coastal marine, siliciclastic environment.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:taxonomic analysis
Collection method comments: COLLECTOR: Presumably Y. Honda (c. 1984) and Suni and Yamaguchi (c. 1969). REPOSITORY: Uknown repository.
Taxonomic list comments:COVERAGE: Exhaustive for gastropoda, bivalvia and scaphopoda. NOMENCLATURE: Authoritative publication, using moderately recent nomenclature, subgenus and species level designations.
Metadata
Database number:70597
Authorizer:A. Hendy Enterer:A. Hendy
Modifier:A. Hendy Research group:marine invertebrate
Created:2007-03-29 19:14:54 Last modified:2025-02-22 15:12:02
Access level:authorizer only Released:2008-03-29 19:14:54
Creative Commons license:CC0
Reference information

Primary reference:
23698. Y. Honda. 1989. Paleogene molluscan faunas from the Kushiro Coal Field, Eastern Hokkaido. Tohoku University, Science Report, 2nd series 60(1):1-137 [A. Hendy/A. Hendy]