Norian

System/
Period
Series/
Epoch
Stage/
Age
Age (Ma)
Jurassic Lower/
Early
Hettangian younger
Triassic Upper/
Late
Rhaetian 201.3–208.5
Norian 208.5–~228
Carnian ~228–~235
Mid/
Middle
Ladinian ~235–~242
Anisian ~242–247.2
Lower/
Early
Olenekian 247.2–251.2
Induan 251.2–252.2
Permian Lopingian Changhsingian older
Subdivision of the Triassic system
according to the IUGS, as of July 2012.

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 ~228 to 208.5 million years ago.[1] It was preceded by the Carnian and succeeded by the Rhaetian.[2]

Stratigraphic definitions

The Norian was named after the Noric Alps in Austria. The stage was introduced into scientific literature by Austrian geologist Edmund Mojsisovics von Mojsvar in 1869.

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:

Palaeontology

Dinosaurs

Dinosaurs of the Norian
Taxa Presence Location Description Images
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
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.
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

Pterosaurs of the Norian
Taxa Presence Location Description Images

Crocodylomorphs

Crocodylomorphs of the Norian
Taxa Presence Location Description Images

†Ichthyosaurs

Ichthyosaurs of the Norian
Taxa Presence Location Description Images

Shonisaurus

  1. Shonisaurus popularis
Nevada, USA

†Dinosauromorphs (non-dinosaurian)

Non-dinosaurian dinosauromorphs of the Norian
Taxa Presence Location Description Images
New Mexico

†Placodonts

Placodonts of the Norian
Taxa Presence Location Description Images

†Crurotarsans (non-crocodylomorph)

Non-crocodylomorph Crurotarsans of the Norian
Taxa Presence Location Description Images
Lesotho

Mammalia

Mammalia[3] of the Norian
Taxa Presence Location Description Images
Norian to Sinemurian Greenland and Western Europe A Late Triassic-Early Jurassic symmetrodontan.

Temnospondyls

Temnospondyls of the Norian
Taxa Presence Location Description Images
Arizona
Arizona

†Ammonites

References

Notes

  1. According to Gradstein et al. (2004). Brack et al. (2005) give 226 to 207 million years
  2. See for a detailed geologic timescale Gradstein et al. (2004)
  3. 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.

Literature

External links

Triassic Period
Lower/Early Triassic Middle Triassic Upper/Late Triassic
Induan |Olenekian Anisian | Ladinian Carnian | Norian
Rhaetian
This article is issued from Wikipedia - version of the 11/10/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.