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Second age of the late Triassic
Norian −255 —
–
−250 —
–
−245 —
–
−240 —
–
−235 —
–
−230 —
–
−225 —
–
−220 —
–
−215 —
–
−210 —
–
−205 —
–
−200 —
← Full recovery of woody trees
[2]
Subdivision of the Triassic according to the
ICS , as of 2021.
[5] Vertical axis scale: millions of years ago.
Name formality Formal Celestial body
Earth Regional usage Global (
ICS ) Time scale(s) used ICS Time Scale Chronological unit
Age Stratigraphic unit
Stage Time span formality Formal Lower boundary definition Not formally defined
[6] Lower boundary definition candidates Base of
Stikinoceras kerri ammonoid zone and near
FAD of
Metapolygnathus echinatus within the
M. communisti
Conodont zones
[6] Lower boundary GSSP candidate section(s)
Upper boundary definition Not formally defined
[6] Upper boundary definition candidates
Upper boundary GSSP candidate section(s)
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 .
[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
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:
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.
[10]
Notable formations
* Tentatively assigned to the Norian; age estimated primarily via terrestrial tetrapod
biostratigraphy (see
Triassic land vertebrate faunachrons )
References
Notes
^ Widmann, Philipp; Bucher, Hugo; Leu, Marc; et al. (2020).
"Dynamics of the Largest Carbon Isotope Excursion During the Early Triassic Biotic Recovery" . Frontiers in Earth Science . 8 (196): 196.
Bibcode :
2020FrEaS...8..196W .
doi :
10.3389/feart.2020.00196 .
^ McElwain, J. C.; Punyasena, S. W. (2007). "Mass extinction events and the plant fossil record". Trends in Ecology & Evolution . 22 (10): 548–557.
doi :
10.1016/j.tree.2007.09.003 .
PMID
17919771 .
^
Retallack, G. J.;
Veevers, J. ; Morante, R. (1996).
"Global coal gap between Permian–Triassic extinctions and middle Triassic recovery of peat forming plants" . GSA Bulletin . 108 (2): 195–207.
Bibcode :
1996GSAB..108..195R .
doi :
10.1130/0016-7606(1996)108<0195:GCGBPT>2.3.CO;2 . Retrieved 2007-09-29 .
^ Payne, J. L.; Lehrmann, D. J.; Wei, J.; Orchard, M. J.; Schrag, D. P.; Knoll, A. H. (2004).
"Large Perturbations of the Carbon Cycle During Recovery from the End-Permian Extinction" . Science . 305 (5683): 506–9.
Bibcode :
2004Sci...305..506P .
doi :
10.1126/science.1097023 .
PMID
15273391 .
S2CID
35498132 .
^ Ogg, James G.; Ogg, Gabi M.; Gradstein, Felix M. (2016). "Triassic". A Concise Geologic Time Scale: 2016 . Elsevier. pp. 133–149.
ISBN
978-0-444-63771-0 .
^
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 .
^ Rigo, Manuel; Bertinelli, Angela; Concheri, Giuseppe; Gattolin, Giovanni; Godfrey, Linda; Katz, Miriam E.; Maron, Matteo; Mietto, Paolo; Muttoni, Giovanni; Sprovieri, Mario; Stellin, Fabio; Mariachiara, Zaffani (2016).
"The Pignola-Abriola section (southern Apennines, Italy): a new GSSP candidate for the base of the Rhaetian Stage" . Lethaia . 49 (3): 287–306.
doi :
10.1111/let.12145 .
hdl :
11577/3157425 .
ISSN
1502-3931 . {{
cite journal }}
: CS1 maint: multiple names: authors list (
link )
^ 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)
^ 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