Ornatenton Formation
Jurassic marine formation in Germany
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The Ornatenton Formation is a Jurassic marine formation in Germany that is middle Callovian in age. The formation represents a shallow marine environment.[1][2][3]
| Ornatenton Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Geological formation |
| Sub-units | Macrocephalae Subformation, Ornatenton Subformation, Glaukonitsandmergel Subformation |
| Underlies | Kandern Formation, Impressamergel Formation |
| Overlies | Variansmergel Formation |
| Thickness | up to 50 m (160 ft) |
| Lithology | |
| Primary | Mudstone |
| Other | Sandstone |
| Location | |
| Country | Germany |
| Type section | |
| Named for | Kosmoceras ornatum |
| Named by | Bloos, Dietl and Schweigert |
| Year defined | 2005 |
History and naming
The Ornatenton Formation was named by Gert Bloos, Gerd Dietl and Günter Schweigert in 2005. This southern German Jurassic layer had already been previously referred to as the 'Ornatenton' by Friedrich August von Quenstedt in 1857. The formation was named after the ammonite Ammonitus ornatus, today known as Kosmoceras ornatum. A type locality has not yet been determined.
Definition and distribution area
The Ornatenton Formation is composed mainly of mudstone with some iron-oolith benches, glauconitic sandstones, and a horizon of carbonate concretions. It stretches from the Eastern Alps to the Rhine valley, and the facies area stretches into Switzerland where it is known as the 'argovian' facies. In southern Germany, the formation is underlain by the Variansmergel Formation and regionally overlapped by the Kandern or Impressamergel Formation, while in the Wutach area it is replaced by the Wutach Formation. Further east, in the French Alps, it dovetails with the Sengenthal Formation. Its thickness varies from a few meters in the Swabian Jura up to about 50 metres (160 ft) in the Plettenberg area.
Time frame and subdivision
The Ornatenton Formation is divided into three subformations: the Macrocephalae Subformation, the Ornatenton Subformation, and the Glaukonitsandmergel Subformation. Some of the sediments of the Ornatenton Formation are dated to the upper Bathonian, but most were deposited during the Callovian. The formation locally reaches into the lower Oxfordian.
Fossil content
The remains of dinosaurs and marine reptiles are known from the Ornatenton Formation alongside a rich invertebrate fauna including the oyster Gryphaea dilatata along with the ammonites Clydoniceras discus, Bullatimorphies bullatus, Macrocephalites gracilis, Reineckeia anceps, Erymnoceras coronatum, Peltoceras athleta, Quenstedtoceras lamberti, Quenstedtoceras mariae, and Cardioceras cordatum.[1][4][5]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Dinosaurs
Theropods
| Theropods of the Ornatenton Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Image |
| Wiehenvenator | W. albati | Partial skeleton belonging to a single individual.[1] | A large megalosaurine megalosaurid |  | ||
| Torvosaurus | T. sp | Fragmentary maxilla[6] | A large megalosaurine megalosaurid |  | ||
| Megalosauroidea indet. | unknown | Pedal phalanx[6] | Probably belongs either to the same specimen as the Ornatenton maxilla of Torvosaurus or the holotype of Wiehenvenator[6] | |||
Thalattosuchians
| Thalattosuchians of the Ornatenton Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Image |
| Metriorhynchus | M. sp. | A skull and lower jaws.[1] | A metriorhynchine metriorhynchid |  | ||
Plesiosaurs
| Plesiosaurs of the Ornatenton Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Image |
| Liopleurodon | L. sp. | Vertebral centra and teeth.[1] | A thalassophonean pliosaurid |  | ||
Crustaceans
| Crustaceans of the Ornatenton Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Image |
| Eumorphia[7] | E. fabianmuelleri | A mecochirid decapod | ||||
Echinoderms
| Echinoderms of the Ornatenton Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Image |
| Borszczia[8] | B. wallueckensis | A cribeline paxillosidan | ||||
| Diademopsis[9] | D. wallueckensis | A pedinid sea urchin | ||||
| Plumaster[8] | P. echinoides | a plumasterid sea star | ||||
| Polycidaris[9] | P. vadeti | A polycidarid pencil urchin | ||||
| Procidaris[9] | P. relicta | A miocidarid pencil urchin | ||||
