Atsunai Fm - AT-1: Middle Miocene, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Gastropoda - Naticidae
Euspira sp. Agassiz 1837
Tectonatica sp. Sacco 1890
Gastropoda - Turritellidae
Turritella sp. Lamarck 1799
Mesalia sp. Gray 1847
Gastropoda - Turbinidae
Homalopoma sp. Carpenter 1864
Scaphopoda - Dentaliida - Dentaliidae
Bivalvia - Cardiida - Cardiidae
Bivalvia - Cardiida - Tellinidae
Bivalvia - Venerida - Veneridae
Bivalvia - Arcida - Glycymerididae
Bivalvia - Arcida - Arcidae
Bivalvia - Pectinida - Pectinidae
see common names

Geography
Country:Japan
Coordinates: 43.1° North, 143.8° East (view map)
Paleocoordinates:43.0° North, 141.0° East (Wright 2013)
Basis of coordinate:estimated from map
Geographic resolution:outcrop
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 Member:Ishiizawa Sandstone
Stratigraphic resolution:bed
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From Atsunai Fm, which overlies the Tokomuro Fm (Early Miocene) of the Atsunai Gp, and is overlain by the Shiranuka Fm (Late Miocene-Pliocene). THICKNESS: From bed with formation that attains a thickness of 700 m. AGE: Middle Miocene on the basis of molluscan biostratigraphy; Kawabata stage. STRATIGRAPHIC POSITION: From member at the base of the Atsunai Fm.
Lithology and environment
Primary lithology:medium,ferruginous lithified sandstone
Includes fossils?Y
Lithology description: SPECIFIC LITHOLOGY: Iron-stained, medium-grained sandstone. LITHIFICATION: Lithified, on the basis of facies description.
Environment:transition zone/lower shoreface
Geology comments: ENVIRONMENT: Assemblage appears to be derived from an shallow shelf siliciclastic environment. TEMPERATURE: Mollusca suggest temperate water conditions.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:biostratigraphic analysis
Collection method comments: COLLECTOR: Y. Honda. REPOSITORY: Institute of Geology and Paleontology, Tohoku University, Sendai, Japan (IGPS).
Taxonomic list comments:COVERAGE: Exhaustive for gastropoda and bivalvia. NOMENCLATURE: Authoritative publication with subgeneric and species-level assignments.
Metadata
Database number:70399
Authorizer:A. Hendy Enterer:A. Hendy
Research group:marine invertebrate
Created:2007-03-21 21:56:07 Last modified:2025-02-22 15:12:02
Access level:authorizer only Released:2007-03-21 21:56:06
Creative Commons license:CC0
Reference information

Primary reference:
23610. Y. Honda. 1988. Molluscan fossils from the Atsunai Group, Kushiro Coal Field, Eastern Hokkaido, Northern Japan. Sato Ho-on Kai Special Publication (Profesoor T. Kotaka Commemorartive Volume) 351-363 [A. Hendy/A. Hendy]