Nakasato, Sebayashi trackway site (Cretaceous of Japan)

Where: Gunma, Japan (41.0° N, 140.4° E: paleocoordinates 54.7° N, 136.3° E)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Sebayashi Formation (Sanchu Group), Early/Lower Albian (112.0 - 109.0 Ma)

• strata are part of the Sanchu Terrane

• group of beds-level stratigraphic resolution

Environment/lithology: delta plain; gray, silty sandstone and shale

• "The deposits having the dinosaur footprints have been presumed to be a part of a mouth bar in a delta, reflecting flood deposition. The flood probably represented a southerly flowing fluvial system, showing a southerly opened deltaic plain, inferred on the basis of asymmetric current ripple marks."
• "The cliff on which the dinosaur footprints are preserved is made up of a fine-grained sandstone bed, 21 cm thick; average grain size is 2.3 phi and mud content is 8.55%. The bed composing the surface of the cliff is overlain by a shale bed 16.5 cm thick. The shale bed consists of thin layers; the lowest layer, composed of numerous films, is 1.5 cm thick. The lowest film is about 0.5 mm thick."

Size class: macrofossils

Preservation: trace

Collection methods: surface (in situ), peel or thin section,

Primary reference: M. Matsukawa and I. Obata. 1985. Dinosaur footprints and other indentation in the Cretaceous Sebayashi Formation, Sebayashi, Japan. Bulletin of the National Science Museum, Tokyo, Series C 11(1):9-36 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 13336: authorized by Matthew Carrano, entered by Matthew Carrano on 27.02.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

• includes "fresh- and brackish-water bivalves and gastropods and terrestrial plant remains". Some marine bivalves are also considered allochthonous.
Show authors, comments, and common names
Reptilia
 Dinosauria -
Dinosauria indet.
Bivalvia
 Hiatellida - Hiatellidae
Panopea sp.
Panopea sp. Menard 1807 clam
 Cardiida - Neomiodontidae
Costocyrena radiatostriata, Protocyprina aff. naumanni
 Carditida - Astartidae
Astarte (Yabea) shinanoensis
 Trigoniida - Trigonioididae
Nippononaia ryosekiana
 Ostreida - Ostreidae
Ostrea sp.
Ostrea sp. Linnaeus 1758 oyster