Also known as Locality 4
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 52105: authorized by Arnold Miller, entered by Kate Bulinski on 22.07.2005