TheNorian is a division of theTriassicPeriod. It has the rank of anage (geochronology) orstage (chronostratigraphy). It lasted from ~227.3 to 205.7million years ago. It was preceded by theCarnian and succeeded by theRhaetian.[8]
| Norian | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ~227.3 – ~205.7Ma | |||||||||||||||||||||||
| Chronology | |||||||||||||||||||||||
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| Etymology | |||||||||||||||||||||||
| Name formality | Formal | ||||||||||||||||||||||
| Usage information | |||||||||||||||||||||||
| Celestial body | Earth | ||||||||||||||||||||||
| Regional usage | Global (ICS) | ||||||||||||||||||||||
| Time scale(s) used | ICS Time Scale | ||||||||||||||||||||||
| Definition | |||||||||||||||||||||||
| Chronological unit | Age | ||||||||||||||||||||||
| Stratigraphic unit | Stage | ||||||||||||||||||||||
| Time span formality | Formal | ||||||||||||||||||||||
| Lower boundary definition | Not formally defined[6] | ||||||||||||||||||||||
| Lower boundary definition candidates | Base ofStikinoceras kerri ammonoid zone and nearFAD ofMetapolygnathus echinatus within theM. communistiConodont zones[6] | ||||||||||||||||||||||
| Lower boundary GSSP candidate section(s) | |||||||||||||||||||||||
| Upper boundary definition | Not formally defined[6] | ||||||||||||||||||||||
| Upper boundary definition candidates |
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| Upper boundary GSSP candidate section(s) |
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Stratigraphic definitions
edit
The Norian was named after theNoric Alps inAustria. The stage was introduced into scientific literature by Austrian geologistEdmund Mojsisovics von Mojsvar in 1869.
The Norian Stage begins at the base of theammonitebiozones ofKlamathites macrolobatus andStikinoceras kerri, and at the base of theconodont biozones ofMetapolygnathus communisti andMetapolygnathus primitius. A global reference profile for the base (aGSSP) had in 2009 not yet been appointed.
The top of the Norian (the base of the Rhaetian) is at the first appearance of ammonite speciesCochloceras amoenum. The base of the Rheatian is also close to the first appearance of conodont speciesMisikella spp. andEpigondolella mosheri and theradiolarid speciesProparvicingula moniliformis.
In theTethys domain, the Norian Stage contains six ammonite biozones:
- zone ofHalorites macer
- zone ofHimavatites hogarti
- zone ofCyrtopleurites bicrenatus
- zone ofJuvavites magnus
- zone ofMalayites paulckei
- zone ofGuembelites jandianus
Subages
editThe 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.
TheRevueltian land-vertebratefaunachron corresponds to part of the Norian.[9]
Notable formations
edit- Calcare di Zorzino (Italy)
- Caturrita Formation (Rio Grande do Sul, Brazil)
- Chinle Formation (SW USA)
- Cow Branch Formation (North Carolina and Virginia, USA)
- Dolomia di Forni (Italy)
- Los Colorados Formation (Argentina)
- Stubensandstein (Germany)
- Trossingen Formation (Norian – Rhaetian) (Switzerland and Germany)
References
editNotes
edit- ^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. Retrieved2007-09-29.
- ^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.
- ^"International Chronostratigraphic Chart"(PDF).International Commission on Stratigraphy. December 2024. RetrievedJanuary 1, 2025.
- ^abcdefghijk"Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved23 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.Bibcode:2016Letha..49..287R.doi:10.1111/let.12145.hdl:11577/3157425.ISSN 1502-3931.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^"ICS - Chart/Time Scale"(PDF). Archived fromthe original(PDF) on 2025-01-01. Retrieved2025-01-14.
- ^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. Retrieved17 November 2021.
Literature
edit- 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, Episodes28(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
edit- GeoWhen Database - Norian
- Upper Triassic timescale, at the website of the subcommission for stratigraphic information of the ICS
- Norges Network of offshore records of geology and stratigraphy:Stratigraphic charts for the Triassic,[1] and[2]