Oguwa Formation, Chikanaga area: Turonian, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Malacostraca - Decapoda - Palinuridae
Gastropoda - Naticidae
Gyrodes sp. Conrad 1860
Bivalvia - Lucinida - Lucinidae
Lucinoma sp. Dall 1901
Bivalvia - Myalinida - Inoceramidae
Inoceramus cf. hobetsensis Nagao and Matsumoto 1939
Inoceramus cf. teshioensis Nagao and Matsumoto 1939
Cephalopoda - Ammonitida - Acanthoceratidae
Romaniceras sp. Spath 1923
Romaniceras cf. deverioides (de Grossouvre 1889)
Cephalopoda - Ammonitida - Collignoniceratidae
Cephalopoda - Ammonitida - Tetragonitidae
Cephalopoda - Ammonitida - Desmoceratidae
Cephalopoda - Ammonitida - Nostoceratidae
Eubostrychoceras sp. Matsumoto 1967
Cephalopoda - Ammonitida - Scaphitidae
Otoscaphites sp. Wright 1953
Cephalopoda - Nautilida - Nautilidae
Cymatoceras sp. Hyatt 1884
Echinoidea - Spatangoida - Hemiasteridae
see common names

Geography
Country:Japan
Coordinates: 33.3° North, 132.8° East (view map)
Paleocoordinates:39.1° North, 136.8° East (Wright 2013)
Geographic resolution:local area
Time
Period: Cretaceous Epoch: Late Cretaceous
Stage: Turonian 10 m.y. bin: Cretaceous 6
Key time interval: Turonian
Age range of interval: 93.9 - 89.8 m.y. ago
Stratigraphy
Geological group:Shimanto Formation:Oguwa
Stratigraphic resolution:formation
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From the Oguwa Fm (Turonian) of the lower Shimanto Group and Shimanto Supergroup, overlying the Shimoono Fm (Middle and Upper Albian) and overlain by the Furushiroyama Fm (Coniacian). AGE: Turonian. STRATIGRAPHIC POSITION: List not specified to any part of the formation.
Lithology and environment
Primary lithology: "siliciclastic"
Includes fossils?Y
Lithology description: SPECIFIC LITHOLOGY: Lithology, unknown, presumably siliciclastic. LITHIFICATION: No evidence for lithification.
Environment:offshore
Geology comments: STRATIGRAPHY and STRUCTURE: The Shimanto Supergroup is a thick clastic sequence with minor basic volcanic rocks, chert and limestone. The Aptian, Albian, Turonian, and Conacian to Santonian strata are in fault contact with one another. The Lower Cretaceous, except for the Lower Aptian is regarded as rather deep offshore deposits, while the Upper Cretaceous as neritic, shelf deposits.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:general faunal/floral analysis
Collection method comments: COLLECTOR: Collector unknown. REPOSITORY: Repository unknown.
Taxonomic list comments:COVERAGE: Suspected to only include biostratigraphically important taxonomic groups (i.e. inoceramids and ammonoids). NOMENCLATURE: Not an authoritative publication, but using subgeneric and species-level designations.
Metadata
Database number:65022
Authorizer:A. Hendy Enterer:A. Hendy
Research group:marine invertebrate
Created:2006-09-18 08:59:46 Last modified:2025-02-22 15:12:02
Access level:the public Released:2006-09-18 08:59:45
Creative Commons license:CC0
Reference information

Primary reference:
18725.1% 11980Y. Teraoka, I. Obata, and I. Mizuno. 1980. Stratigraphy of the Shimanto Supergroup in the Chikanaga area, west Shikoku, with special reference to the Miyakoan and Gyliakian Series. Bulletin of the Geological Survey of Japan 31(7):307-319 [A. Hendy/A. Hendy]