Higashi-Tanakura Group Kubota Fm Molluscan Fauna Locality 7 (Miocene of Japan)

Also known as Locality 7

Where: Japan (37.5° N, 140.0° E: paleocoordinates 38.9° N, 138.4° E)

• coordinate based on political unit

• local area-level geographic resolution

When: Kubota Formation (Higashi-Tanakura Group), Late/Upper Miocene (11.6 - 5.3 Ma)

• Higbashi-Tanajura group is a marine representative of the regressive Genjigawa stage

• formation-level stratigraphic resolution

Environment/lithology: marginal marine; lithified, medium-grained, micaceous, gray, blue, argillaceous sandstone and lithified, fine-grained, micaceous, black, blue, argillaceous sandstone

• Lateral and vertical changes of lithofacies indicate that the group had been accumulated in the course of a local transgression and regression. Sediment is supplied from Abukuma mountain block. Paleogeographically, Higashi-Tanakura group is the deposits filling up a small shallow embayment open to the north.
• massive medium sandstone in the lower part and massive fine sandstone with intercalations of several ash tuff layers in the central and upper part of the basin...characterized by abundant occurrence of molluscan fossils. Bluish-gray medium to fine sandstone covers (beds below) and consists mainly of quartz and mica grains with argillaceous materials. It is fine in the west, and becomes coarser eastward...The medium sandstone is covered by massive fine sandstone in the southern area. This fine sandstone is bluish-black colored, massive, homogeneous, argillaceous and rich in mica flakes. Several white fine ash tuff layers are intercalated in the middle part of the fine sandstone. They are concentrated in three restricted horizons. Coarse sandstone lenses, rich in shell fragments and quartz grains are found at Okada. They are more than 10m in thickness and are contemporaneous with the fine sandstone and diminish laterally into the fine sandstone.

Primary reference: Y. Iwasaki. 1970. The Shiobara-type Molluscan Fauna: An ecological analysis of fossil molluscs. Journal of the faculty of science, University of Tokyo, Section 2 17(3):351-444 [A. Miller/K. Bulinski/K. Bulinski]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 52112: authorized by Arnold Miller, entered by Kate Bulinski on 25.07.2005

Creative Commons license: CC BY (attribution)

Taxonomic list

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Gastropoda
 Cerithioidea - Cerithiidae
Cerithium kobelti
Cerithium kobelti cerith snail
 Cerithioidea - Turritellidae
Turritella tanaguraensis
 Neotaenioglossa - Calyptraeidae
Crepidula sp.
Crepidula sp. Lamarck 1799 slipper shell
 Sorbeoconcha - Naticidae
"Neverita kiritaniana" = Glossaulax didyma, "Sinum yabei" = Sinum ineptum
"Neverita kiritaniana" = Glossaulax didyma Röding 1798 moon snail
"Sinum yabei" = Sinum ineptum Yokoyama 1924 moon snail
 Neogastropoda - Nassariidae
Nassarius acutidentatus
 Neogastropoda - Buccinidae
Phos iwakianus, Siphonalia cf. spadicea
Phos iwakianus true whelk
 Neogastropoda - Cancellariidae
Cancellaria hukusimana
Bivalvia
 Pectinida - Anomiidae
Anomia cytaeum
 Ostreida - Ostreidae
Ostrea gravitesta
 Arcida - Arcidae
Anadara ninohensis
Anadara ninohensis ark
Dominant species at locality
 Cardiida - Cardiidae
Laevicardium shiobarense
 Cardiida - Tellinidae
"Macoma incongrua" = Macoma (Macoma) incongrua
"Macoma incongrua" = Macoma (Macoma) incongrua Martens 1865 tellin clam
 Cardiida - Ungulinidae
"Felaniella usta" = Diplodonta
"Felaniella usta" = Diplodonta clam
 Cardiida - Veneridae
"Protothaca tateiwai" = Leukoma, Dosinia kaneharai, Dosinia japonica, Mercenaria chitaniana
"Protothaca tateiwai" = Leukoma venus clam
Dosinia kaneharai venus clam
Dosinia japonica venus clam
 Lucinida - Lucinidae
"Lucinoma annulata" = Lucinoma annulatum
"Lucinoma annulata" = Lucinoma annulatum Reeve 1850 clam