Loc. 139 and Loc. 146 [Okinoshima Fm]: Bartonian, Japan
collected by Kamada

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Bivalvia - Cardiida - Veneridae
Pitar takashimaensis
R category
Pitar kyushuensis
A category
Cephalopoda - Nautilida - Nautilidae
Eutrephoceras japonicum (Shimizu 1926)
R category
Gastropoda - Turritellidae
Turritella sp. Lamarck 1799
F category
see common names

Geography
Country:Japan
Coordinates: 32.9° North, 129.6° East (view map)
Paleocoordinates:38.1° North, 124.0° East
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period: Paleogene Epoch: Eocene
Stage: Bartonian 10 m.y. bin: Cenozoic 3
Key time interval: Bartonian
Age range of interval: 41.2 - 37.71 m.y. ago
Stratigraphy
Formation:Okinoshima
Stratigraphic resolution:bed
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From the Okinoshima Fm, which conformably overlies the Hashima Fm and is unconformably overlain by the Iojima Fm. AGE: Late Eocene according to foraminiferal biostratigraphy in Asano (1958), and correlated to the Sakasegawa Shale. Kobayashi and Kamada (1959) suggest that the formation could even range from Middle-Late Eocene. According to foraminiferal and molluscan biostratigraphy, the formation is assigned in age to the Auverisian to the Bartonian (Upper Eocene). The Okinoshima Formation falls within calcareous nannofossil Subzones CP14a–CP15b of Okada and Bukry (1980) and planktic foraminiferal Zones E10–E13 of Berggren and Pearson (2005), dating to the middle Eocene. The Okinoshima Formation including calcareous nannofossils such as Reticulofenestra umbilica and Discoaster barbadiensis, indicating Zones CP14–CP15 and planktic foraminifer, Acarinina primitiva, representing Zone P14 or older (Yamaguchi et al. 2004). These biozones of planktic microfossils assign the Okinoshima Formation to 43.5–39.0 Ma (Yamaguchi & Kamiya, 2007).
STRATIGRAPHIC POSITION: From bed of unknown thickness within 150 m thick formation.
Lithology and environment
Primary lithology: lithified "siliciclastic"
Lithology description: SPECIFIC LITHOLOGY: Lithology not stated in text, but is likely siliciclastic. LITHIFICATION: Lithified, on the basis of figured specimens.
Environment:offshore
Geology comments: ENVIRONMENT: The biofacies consists of samples from muddy sandstones, sandy mudstones, and mudstones, which represent bioturbation and include few sedimentary structures that indicate wave and tidal influences. The planktic/total foraminifer ratios (P/T ratios) from the Okinoshima Formation is less than 0.03, suggesting water depths shallower than about 100–150 m. The lithofacies, P/T ratios, and molluscan assemblages indicate shallow-marine environments with little to no influence by wave and tidal action. Hence, the biofacies correlates with outer-shelf environments under warm-water conditions.
Taphonomy
Modes of preservation:body,cast,mold/impression
Size of fossils:macrofossils
Articulated whole bodies:some
Spatial resolution:autochthonous
Collection methods and comments
Collection methods:surface (in situ),field collection
Reason for describing collection:paleoecologic analysis
Collectors:Kamada
Collection method comments: COLLECTOR: Y. Kamada and graduates students Nagasaki University, c. 1950's. REPOSITORY: Nagasaki and Tokyo University.
Taxonomic list comments:COVERAGE: Exhaustive for Bivalvia, Gastropoda, and Cephalopoda. NOMENCLATURE: Authoritative publication for cephalopods, but general for other taxa. Nomenclature is somewhat antiquated, but identified to species-resolution.
Metadata
Database number:81230
Authorizer:A. Hendy Enterer:A. Hendy
Modifier:M. Clapham Research group:marine invertebrate
Created:2008-06-11 08:08:46 Last modified:2019-09-18 22:12:47
Access level:the public Released:2008-06-11 08:08:46
Creative Commons license:CC BY
Reference information

Primary reference:
27378. T. Kobayashi and Y. Kamada. 1959. An Eocene Nautiloid from Kyushu, Japan. Japanese Journal of Geology and Geography 30:105-125 [A. Hendy/A. Hendy]