Hakobuchi Formation
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| Hakobuchi Formation | |
|---|---|
| Stratigraphic range: Early | |
| Type | Geological formation |
| Unit of | Yezo Group |
| Underlies | Ishikari Group, Poronai Group |
| Overlies | Haborogawa Formation, Kashima Formation |
| Thickness | Over 450 metres (1,480 ft) |
| Lithology | |
| Primary | Mudstone, Siltstone, Sandstone |
| Other | Tuffite |
| Location | |
| Location | Lua error: callParserFunction: function "#coordinates" was not found. |
| Region | East Asia |
| Country | File:Flag of Japan.svg Japan |
| Extent | Hokkaido |
Hakobuchi Formation (Japan) | |
The Hakobuchi Formation is a geological formation in Hokkaido, Japan. It is the uppermost unit of the Yezo Group, being early Maastrichtian in age. It consists of bioturbated glauconitic sandstones, siltstones and conglomerates with coaly mudstone and minor tuffite. It was deposited in a continental shelf setting.[1] It is noted for its fossil content with the invertebrates mainly consisting of bivalves and ammonites. With vertebrates including the mosasaurs Mosasaurus hobetsuensis and Phosphorosaurus ponpetelegans.[2] As well the sea turtle Mesodermochelys[3] and the hadrosaurid dinosaur Kamuysaurus.[4]
Fossil content
[edit | edit source]Color key
|
Notes Uncertain or tentative taxa are in small text; |
Dinosaurs
[edit | edit source]Ornithopods
[edit | edit source]| Ornithopods of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Kamuysaurus[5] | K. japonicus | A edmontosaurin saurolophine | ||||
Mosasaurs
[edit | edit source]| Mosasaurs of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Mosasaurus | M. hobetsuensis | A mosasaurine mosasaurid | ||||
| Phosphorosaurus | P. ponpetelegans | A halisaurine mosasaurid | ||||
Turtles
[edit | edit source]| Turtles of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Mesodermochelys | M. undulatus | A dermochelyid turtle | ||||
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Fish
[edit | edit source]Cartilaginous Fish
[edit | edit source]| Cartilaginous Fish of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Callorhinchus[6] | C. orientalis | A callorhinchid chimaeran | ||||
Ray-finned Fish
[edit | edit source]| Cartilaginous Fish of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Acipenseridae[7] | A sturgeon | |||||
Molluscs
[edit | edit source]Bivalves
[edit | edit source]| Bivalves of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Inoceramus | I. nipponicus | A inoceramid bivalve | ||||
Cephalopods
[edit | edit source]| Cephalopods of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Pachydiscus | P. japonicus | A pachydiscid ammonite | ||||
Gastropods
[edit | edit source]| Gastropods of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
Paleoflora
[edit | edit source]| Plants of the Hakobuchi Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Mukawastrobus | M. satoi | A cypress | ||||
| Nilssonia | N. yezoensis | A cycad | ||||
References
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- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Hirayama R, Chitoku T. (1996). "Family Dermochelyidae (Superfamily Chelonioidea) from the Upper Cretaceous of North Japan". Transactions and proceedings of the Palaeontological Society of Japan. New series 184: 597-622. online, retrieved 28 July 2008
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).