R4018b, Obirashibe River, Obira area: Middle Turonian, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Cephalopoda - Phylloceratida - Phylloceratidae
5 specimens
Cephalopoda - Ammonitida - Scaphitidae
11 specimens
6 specimens
Scaphites planus (Yabe 1910)
18 specimens
Cephalopoda - Ammonitida - Nostoceratidae
1 specimen
Cephalopoda - Ammonitida - Diplomoceratidae
Scalarites sp. Wright and Matsumoto 1954
2 specimens
Cephalopoda - Ammonitida - Tetragonitidae
6 specimens
Tetragonites glabrus (Jimbo 1910)
8 specimens
Cephalopoda - Ammonitida - Desmoceratidae
Damesites ainuanus Matsumoto 1957
1 specimen
4 specimens
see common names

Geography
Country:Japan
Coordinates: 44.1° North, 141.9° East (view map)
Paleocoordinates:51.6° North, 141.8° East (Wright 2013)
Basis of coordinate:estimated from map
Geographic resolution:outcrop
Time
Period: Cretaceous Epoch: Late Cretaceous
Stage: Turonian 10 m.y. bin: Cretaceous 6
Key time interval: Middle Turonian Inoceramid zone:  Inoceramus hobetsensis
Age range of interval: 93.9 - 89.8 m.y. ago
Stratigraphy
Formation:Saku
Stratigraphic resolution:bed
Stratigraphy comments: STRATIGRAPHIC RELATIONS: From the Saku Formation of Turonian age, which overlies pre-Cenomanian Cretaceous deposits. THICKNESS: Total unit has thickness of 1200 m. AGE: Middle Turonian, based on ammonite and inoceramid biostratigraphy.
Lithology and environment
Primary lithology:concretionary lithified silty,sandy mudstone
Secondary lithology: lithified conglomeratic sandstone
Includes fossils?Y
Lithology description: GENERAL LITHOLOGY: Mudstone, sandy siltstone, tuffite, and intercalated sandstone and conglomerate; specimens occur in calcite concretions. LITHIFICATION: Lithified, assumed as from concretions.
Environment:coastal indet.
Geology comments: ENVIRONMENT: Inshore to nearshore and nearshore to offshore or deeper waters.
Taphonomy
Modes of preservation:body,concretion
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:taxonomic analysis
Collection method comments: COLLECTOR: Tanable et al. (1977). REPOSITORY: Kyushu University Museum, Fukuoka, Japan.
Taxonomic list comments:COVERAGE: Not exhaustive, only including ammonites, other taxa no listed, but mentioned (i.e. ostreids, trigonians, Glycymeris, drifted plant remains). NOMENCLATURE: Not authoritative publication, but apparently precise nomenclature.
Metadata
Database number:69162
Authorizer:A. Hendy Enterer:A. Hendy
Modifier:M. Clapham Research group:marine invertebrate
Created:2007-02-20 10:40:27 Last modified:2025-02-22 15:12:02
Access level:the public Released:2007-02-20 10:40:27
Creative Commons license:CC0
Reference information

Primary reference:
19937. K. Tanabe. 1979. Paleoecological analysis of ammonoid assemblages in the Turonian Scaphites facies of Hokkaido, Japan. Palaeontology 22(3):609-630 [A. Hendy/A. Hendy]

Secondary references:

82318 K. Tanabe. 2022. Late Cretaceous dimorphic scaphitid ammonoid genus Yezoites from the circum-North Pacific regions. Paleontological Research 26:233-269 [M. Clapham/M. Clapham]