|Subdivision of the Triassic system|
according to the ICS, as of 2018.
The Norian is a division of the Triassic geological period. It has the rank of an age (geochronology) or stage (chronostratigraphy). The Norian lasted from ~227 to 208.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.
- 1 Stratigraphic definitions
- 2 Palaeontology
- 3 References
- 4 External links
The Norian stage begins at the base of the ammonite biozones of Klamathites macrolobatus and Stikinoceras kerri, and at the base of the conodont biozones of Metapolygnathus communisti and Metapolygnathus primitius. A global reference profile for the base (a GSSP) had in 2009 not yet been appointed.
The top of the Norian (the base of the Rhaetian) is at the first appearance of ammonite species Cochloceras amoenum. The base of the Rheatian is also close to the first appearance of conodont species Misikella spp. and Epigondolella mosheri and the radiolarid species Proparvicingula moniliformis.
In the Tethys domain, the Norian stage contains six ammonite biozones:
|Archosauromorphs of the Norian|
|Archosaurs of the Ladinian|
|All across Europe||Zanclodon is the name formally used for fossil material that might actually belongs to at least two genera of dinosaur from the Late Triassic among other genera.|
|Dinosauromorphs of the Norian|
|Dinosaurs of the Norian|
|208 Ma||Avon, England||A disputed dinosaur known from an ilium, maxilla, astragalus, and humerus (it could be a chimera). Agnosphitys lies close to the ancestry of dinosaurs, although exactly where is disputed by researchers. Some consider it a saurischian close to the beginnings of dinosaur evolution, while others consider it a non-dinosaurian dinosauromorph.|
|Carnian to Norian||Chinle Formation, New Mexico, USA|
|Carnian to Norian||Chinle Formation, New Mexico and Arizona and Bull Canyon Formation, New Mexico|
|210 Ma||South Africa||A swift-running basal ornithischian that has the most complete known remains from any Triassic ornithischian, shedding new light on the origin of this group. One of the earliest known ornithischians, it sheds some light on early dinosaur relationships because early dinosaurs are known from mostly incomplete skeletons. Eocursor is known from partial skeletal elements, including skull fragments, spinal elements, pelvis, long leg bones, and unusually large grasping hands.|
|210 Ma||Cooper Canyon Formation, New Mexico, USA||A large coelophysoid named after the giant monster movie character Godzilla.|
|228-201.3 Ma, Norian to Rhaetian||Trossingen Formation, Thuringia, Germany||A coelophysoid that is the best represented Triassic theropod from Europe and one of the largest known.|
|214-204 Ma, Carnian to Norian||Trossingen Formation, Bavaria, Germany|
|Norian to Rhaetian|
|Pterosaurs of the Norian|
|Crurotarsans of the Norian|
|Crocodylomorphs of the Norian|
|Ichthyosaurs of the Norian|
|Placodonts of the Norian|
|Mammalia of the Norian|
|Norian to Sinemurian||Greenland and Western Europe||A Late Triassic-Early Jurassic kuehneotherian.|
|†Temnospondyls of the Norian|
|All over the US and India|
- Pinacoceras layeri
- "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. 2018.
- According to Gradstein et al. (2004). Brack et al. (2005) give 226 to 207 million years
- See for a detailed geologic timescale Gradstein et al. (2004)
- The genera listed are included in Mammalia by Kielan-Jaworowska et al. (2004) but not by those who restrict the taxon to the crown group.
- Brack, P.; Rieber, H.; Nicora, A. & Mundil, R.; 2005: The Global boundary Stratotype Section and Point (GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale, Episodes 28(4), pp. 233–244.
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
- Kielan-Jaworowska, Z.; Cifelli, R. L.; Luo, Zhe-Xi; 2004: Mammals from the Age of Dinosaurs, Columbia University Press.
- Martz, J.W.; 2008: Lithostratigraphy, chemostratigraphy, and vertebrate biostratigraphy of the Dockum Group (Upper Triassic), of southern Garza County, West Texas, Doctoral Dissertation, Texas Tech.