Ashibetsu Fm - Sorachi: Bartonian, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Gastropoda - Neogastropoda - Muricidae
Mizuno 1954
Bivalvia - Unionida - Margaritiferidae
Bivalvia - Venerida - Veneridae
Bivalvia - Venerida - Corbiculidae
Mizuno 1954
Bivalvia - Mytilida - Mytilidae
Mizuno 1954
unclassified
see common names

Geography
Country:Japan
Coordinates: 43.5° North, 142.0° East (view map)
Paleocoordinates:50.4° North, 135.5° East (Wright 2013)
Basis of coordinate:based on nearby landmark
Geographic resolution:local area
Time
Period: Paleogene Epoch: Eocene
Stage: Bartonian 10 m.y. bin: Cenozoic 3
Key time interval: Bartonian
Age range of interval: 41.03 - 37.71 m.y. ago
Stratigraphy
Geological group:Ishikari Formation:Ashibetsu
Stratigraphic resolution:formation
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From Ashibetsu Fm, which overlies the Hiragishi (late Middle Eocene) and underlies the Poronai Fm (Late Eocene) of the Ishikari Gp. THICKNESS: From unit which reaches a thickness of 400 m. AGE: late Middle Eocene according to Takano and Waseda (2003). Referred only to Eocene in Mizuno (1964). STRATIGRAPHIC POSITION: Composite checklist for formation from local area.
Lithology and environment
Primary lithology: lithified sandstone
Secondary lithology: lithified siltstone
Includes fossils?Y
Lithology description: SPECIFIC LITHOLOGY: Sandstone and siltstone, amd coal seams. LITHIFICATION: Assume to be lithified on the basis of age and photgraphic plates of Takano and Osamu (2003).
Environment:fluvial indet.
Geology comments: ENVIRONMENT: Marine and brackish faunal assemblage.
Taphonomy
Modes of preservation:body,cast,mold/impression
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:biostratigraphic analysis
Collection method comments: COLLECTOR: T. Mizuno (c. 1960's). REPOSITORY: Unknown, not stated in text.
Taxonomic list comments:COVERAGE: Exhaustive for bivalvia and gastropoda. NOMENCLATURE: Somewhat antiquated, but with species-level identifications.
Metadata
Database number:70906
Authorizer:A. Hendy, M. Uhen Enterer:A. Hendy, M. Uhen
Modifier:M. Uhen Research group:marine invertebrate
Created:2007-04-11 08:41:53 Last modified:2025-02-22 15:12:02
Access level:authorizer only Released:2008-04-11 08:41:53
Creative Commons license:CC0
Reference information

Primary reference:
23771. A. Mizuno. 1964. Summary of the Paleogene molluscan faunas in North Japan. Geological Survey of Japan Report 207 [A. Hendy/A. Hendy/A. Hendy]

Secondary references:

70583 A. Mizuno. 1954. On Two New Forms of PaleogeneGastropods from Hokkaido, Japan. Venus 18(2):101-108 [M. Uhen/M. Uhen]