| Kitadani Formation | |
|---|---|
| Stratigraphic range: Barremian-Aptian ~ | |
 The Kitadani Dinosaur Quarry Bonebed I, where an outcrop of the Kitadani Formation can be found; the white arrow indicates the location of the type locality of Tyrannomimus fukuiensis. Photographed in c. 2023. | |
| Type | Geological formation |
| Unit of | Tetori Group |
| Underlies | Omichidani Formation |
| Overlies | Akaiwa Formation |
| Thickness | ~100 m (330 ft)[1] |
| Lithology | |
| Primary | Tuff, sandstone, shale |
| Other | Coal |
| Location | |
| Coordinates | 36°06′N 136°36′E / 36.1°N 136.6°E |
| Approximate paleocoordinates | 47°18′N 137°42′E / 47.3°N 137.7°E |
| Region |  Fukui Prefecture |
| Country |  Japan |
| Type section | |
| Named by | Unknown[1] |
  Kitadani Formation (Japan) | |
The Kitadani Formation (Japanese: 北谷層 Kitadani-sō) is a unit of Lower Cretaceous sedimentary rock which crops out near the city of Katsuyama in Fukui Prefecture, Japan, and it is the primary source of Cretaceous-aged non-marine vertebrate fossils in Japan. Dinosaur remains are among the fossils that have been recovered from the formation, but it also preserves a diverse assemblage of plants, invertebrates, and other vertebrates.[2] Most, if not all, of the fossil specimens collected from the Kitadani Formation are reposited at the Fukui Prefectural Dinosaur Museum.[3]
The Kitadani Formation is a unit within the Tetori Group, a major sequence of Lower Cretaceous rocks that is distributed across Fukui, Ishikawa, and Gifu prefectures of western-central Honshu. The Tetori Group exhibits marked lateral variation, and the Kitadani Formation is only present in Fukui Prefecture.[1] The Kitadani Formation comprises interbedded tuffs, sandstones, and shales and reaches a maximum thickness of approximately one hundred meters (~328 feet).[1] It conformably overlies the Akaiwa Formation and is unconformably overlain by the Omichidani Formation.[4] The Kitadani Formation is significant because it is the major source of dinosaur fossils in Japan and because of Japan's unique position along the northeastern margin of Eurasia during the Early Cretaceous.
- ^ a b c d Kusuhashi, N.; Matsuoka, H.; Kamiya, H.; Setoguchi, T. (2002). "Stratigraphy of the late Mesozoic Tetori Group in the Hakusan Region, central Japan : an overview". Memoirs of the Faculty of Science, Kyoto University. Series of Geology and Mineralogy. 59 (1): 9–31.
- ^ Weishampel, D.B.; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, D.B.; Dodson, P.; and Osmólska, H. (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. ISBN 0-520-24209-2.
- ^ "FPDM: Fukui Prefectural Dinosaur Museum".
- ^ Tsubamoto, T.; Rougier, G.W.; Isaji, S.; Manabe, M.; Forasiepi, A.M. (2004). "New Early Cretaceous spalacotheriid "symmetrodont" mammal from Japan". Acta Palaeontologica Polonica. 49 (3): 329–346.