Tokomaru Formation - Kushiro coal field, eastern Hokkaido: Early Miocene, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Bivalvia - Mytilida - Mytilidae
Mytilus tichanovitchi Makiyama 1934
Bivalvia - Cardiida - Tellinidae
Bivalvia - Cardiida - Cardiidae
Serripes sp. Gould 1841
Bivalvia - Venerida - Veneridae
Ezocallista sp. Kamada 1962
Bivalvia - Carditida - Carditidae
Bivalvia - Protobranchia - Sareptidae
Bivalvia - Protobranchia - Yoldiidae
Bivalvia - Protobranchia - Malletiidae
Gastropoda - Turritellidae
Turritella sp. Lamarck 1799
Mesalia sp. Gray 1847
Gastropoda - Naticidae
Tectonatica janthostomoides Kuroda and Habe 1949
see common names

Geography
Country:Japan
Coordinates: 42.8° North, 143.7° East (view map)
Paleocoordinates:43.2° North, 139.9° 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: Early Miocene
Age range of interval: 23.04 - 15.98 m.y. ago
Stratigraphy
Formation:Tokomuro
Stratigraphic resolution:formation
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From Tokomuro Fm of the Atsunai Gp, which overlies the Nuibetsu Fm of the Ombetsu Gp (Late Oligocene) and is overlain by the Atsunai Fm of the Atsunai Gp (Early Miocene). THICKNESS: ~50 m thick. AGE: Early Miocene. STRATIGRAPHIC POSITION: Composite checklist for formation.
Lithology and environment
Primary lithology: lithified siltstone
Secondary lithology: lithified sandstone
Includes fossils?Y
Includes fossils?Y
Lithology description: SPECIFIC LITHOLOGY: Siltstone, sandstone and shale. LITHIFICATION: Assumed to be lithifed on the basis of figured specimens and facies description (i.e. shale).
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:70595
Authorizer:A. Hendy Enterer:A. Hendy
Modifier:A. Hendy Research group:marine invertebrate
Created:2007-03-29 19:05:51 Last modified:2025-02-22 15:12:02
Access level:authorizer only Released:2008-03-29 19:05:51
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]