Norian

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Norian
~227 – ~208.5 Ma
Chronology

The Norian is a division of the

million years ago.[8] It was preceded by the Carnian and succeeded by the Rhaetian.[9]

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

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:

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

faunachron corresponds to part of the Norian.[10]

Notable formations

* Tentatively assigned to the Norian; age estimated primarily via terrestrial tetrapod biostratigraphy (see Triassic land vertebrate faunachrons)

References

Notes

  1. .
  2. .
  3. ^ Retallack, G. J.; . Retrieved 2007-09-29.
  4. .
  5. .
  6. ^ a b c d e f g h i j k "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 23 December 2020.
  7. ISSN 1502-3931.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  8. ^ According to Gradstein et al. (2004). Brack et al. (2005) give 226 to 207 million years
  9. geologic timescale
    Gradstein et al. (2004)
  10. ^ Spielmann, J.A.; Lucas, S.G.; Hunt, A.P. (2013). "The first Norian (Revueltian) rhynchosaur: Bull Canyon Formation, New Mexico, USA" (PDF). New Mexico Museum of Natural History and Science Bulletin. 61: 562. Retrieved 17 November 2021.

Literature

  • 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.

External links

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