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Norian

Norian
~227 – ~208.5 Ma
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionNot formally defined
Lower boundary definition candidatesBase of Stikinoceras kerri ammonoid zone and near FAD of Metapolygnathus echinatus within the M. communisti Conodont zones
Lower boundary GSSP candidate section(s)
Upper boundary definitionNot formally defined
Upper boundary definition candidates
Upper boundary GSSP candidate section(s)
  • Steinbergkogel, Austria
  • Pignola-Abriola, Italy
  • Turkey
  • British Columbia, Canada

The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to 208.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.

Stratigraphic definitions

Cast of a tridactyl footprint of a theropod dinosaur from the Norian of the Czech Republic.

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:

  • zone of Halorites macer
  • zone of Himavatites hogarti
  • zone of Cyrtopleurites bicrenatus
  • zone of Juvavites magnus
  • zone of Malayites paulckei
  • zone of Guembelites jandianus

Subages

The Norian is divided into three global subages or substages:

  • Lacian (lower Norian)
  • Alaunian (middle Norian)
  • Sevatian (upper Norian)

Many older studies considered the Rhaetian to be the uppermost substage of the Norian, though it has subsequently been raised to its own stage.

The Revueltian land-vertebrate faunachron corresponds to part of the Norian.

This page was last updated at 2022-10-12 15:43 UTC. Update now. View original page.

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