Tokmuro Fm - TM-4 (Miocene of Japan)

Where: Japan (42.9° N, 143.8° E: paleocoordinates 43.7° N, 141.9° E)

• outcrop-level geographic resolution

When: Tokmuro Formation, Early/Lower Miocene (23.0 - 16.0 Ma)

• STRATIGRAPHIC RELATIONS: From Tokomuro Fm, which overlies the Nuibetsu Fm (Oligocene) of the Ombetsu Gp, and is overlain by the Atsunai Fm of the Atsunai Gp. THICKNESS: From bed with formation that attains a thickness of 180 m. AGE: Early Miocene on the basis of molluscan biostratigraphy. STRATIGRAPHIC POSITION: Unknown position within formation.

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, tuffaceous, gray, sandy siltstone

• ENVIRONMENT: Assemblage appears to be derived from an offshore shelf siliciclastic environment. TEMPERATURE: Stratigraphically adjacent pollen floras indicate a cool-temperate environment.
• SPECIFIC LITHOLOGY: Alternating beds of gray siltstone, sandstone, sandy tuff, and hard shale. LITHIFICATION: Lithified, on the basis of facies description.

Size class: macrofossils

Collection methods: COLLECTOR: Y. Honda. REPOSITORY: Institute of Geology and Paleontology, Tohoku University, Sendai, Japan (IGPS).

Primary reference: 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]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 70386: authorized by Austin Hendy, entered by Austin Hendy on 21.03.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for gastropoda and bivalvia. NOMENCLATURE: Authoritative publication with subgeneric and species-level assignments.
Show authors, comments, and common names
Bivalvia
 Carditida - Carditidae
Cyclocardia sp.
Cyclocardia sp. Conrad 1867 clam