View source for Carnian

{{Short description|First age of the Late Triassic epoch}}
{{for|the Carnian Alps|Carnic Alps}}
{{Infobox geologic timespan
| name                         = Carnian
| color                        = Carnian
| time_start                   = 237
| time_start_prefix            = ~
| time_end                     = 227
| time_end_prefix              = ~
| image_map                    =
| caption_map                  =
| image_outcrop                = Travenanzes.jpg
| caption_outcrop              = [[Alluvial plain]] red clays of the [[Travenanzes Formation]], upper Carnian, the [[Dolomites]], northern [[Italy]]
| image_art                    =
| caption_art                  =
<!--Chronology-->
| timeline                     = Triassic
| formerly_part_of             =
| partially_contained_in       =
| partially_contains           =
<!--Etymology-->
| name_formality               = Formal
| name_accept_date             =
| alternate_spellings          = Karnian
| synonym1                     =
| synonym1_coined              =
| synonym2                     =
| synonym2_coined              =
| synonym3                     =
| synonym3_coined              =
| nicknames                    =
| former_names                 =
| proposed_names               =
<!--Usage Information-->
| celestial_body               = earth
| usage                        = Global ([[International Commission on Stratigraphy|ICS]])
| timescales_used              = ICS Time Scale
| formerly_used_by             =
| not_used_by                  =
<!--Definition-->
| chrono_unit                  = Age
| strat_unit                   = Stage
| proposed_by                  =
| type_section                 =
| timespan_formality           = Formal
| lower_boundary_def           = [[First appearance datum|FAD]] of the [[Ammonite]] ''[[Daxatina canadensis]]''
| lower_gssp_location          = [[Prati di Stuores]], [[Dolomites]], [[Italy]]
| lower_gssp_coords            = {{Coord|46.5269|N|11.9303|E|display=inline}}
| lower_gssp_accept_date       = 2008<ref>{{cite journal |last1=Mietto |first1=Paolo |last2=Manfrin |first2=Stefano |last3=Preto |first3=Nereo |last4=Rigo |first4=Manuel |last5=Roghi |first5=Guido |last6=Furin |first6=Stefano |last7=Gianolla |first7=Piero |last8=Posenato |first8=Renato |last9=Muttoni |first9=Giovanni |last10=Nicora |first10=Alda |last11=Buratti |first11=Nicoletta |last12=Cirilli |first12=Simonetta |last13=Spötl |first13=Christoph |last14=Ramezani |first14=Jahandar |last15=Bowring |first15=Samuel |title=The Global Boundary Stratotype Section and Point (GSSP) of the Carnian Stage (Late Triassic) at Prati Di Stuores/Stuores Wiesen Section (Southern Alps, NE Italy) |journal=Episodes |date=September 2012 |volume=35 |issue=3 |pages=414–430 |doi=10.18814/epiiugs/2012/v35i3/003 |url=https://stratigraphy.org/gssps/files/carnian.pdf |access-date=13 December 2020}}</ref>
| upper_boundary_def           = Not formally defined<ref name="GSSP Web">{{cite web|title=Global Boundary Stratotype Section and Point |url=https://stratigraphy.org/gssps/|publisher=International Commission of Stratigraphy |access-date=23 December 2020 }}</ref>
| upper_def_candidates         = Base of ''[[Stikinoceras|Stikinoceras kerri]]'' ammonoid zone and near FAD of ''[[Metapolygnathus|Metapolygnathus echinatus]]'' within the ''[[Metapolygnathus|M. communisti]]'' conodont zones<ref name="GSSP Web"/>
| upper_gssp_candidates        =
* [[Black Bear Ridge]], [[British Columbia]], [[Canada]]<ref name="GSSP Web"/>
* [[Pizzo Mondello]], [[Sicily]], Italy<ref name="GSSP Web"/>
<!--Atmospheric and Climatic Data-->
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}}
The '''Carnian''' (less commonly, '''Karnian''') is the lowermost [[stage (stratigraphy)|stage]] of the Upper [[Triassic]] [[series (stratigraphy)|Series]] (or earliest [[age (geology)|age]] of the Late Triassic [[Epoch (reference date)|Epoch]]). It lasted from 237 to 227 [[megaannum|million years ago (Ma)]].<ref>{{Cite web|url=https://stratigraphy.org/timescale/|title = Ics-chart}}</ref> The Carnian is preceded by the [[Ladinian]] and is followed by the [[Norian]]. Its boundaries are not characterized by major extinctions or biotic turnovers, but a climatic event (known as the [[Carnian pluvial episode]] characterized by substantial rainfall) occurred during the Carnian and seems to be associated with important extinctions or biotic radiations.<ref name="dawn">{{Cite journal |last1=Dal Corso |first1=Jacopo |last2=Bernardi |first2=Massimo |last3=Sun |first3=Yadong |last4=Song |first4=Haijun |last5=Seyfullah |first5=Leyla J. |last6=Preto |first6=Nereo |last7=Gianolla |first7=Piero |last8=Ruffell |first8=Alastair |last9=Kustatscher |first9=Evelyn |last10=Roghi |first10=Guido |last11=Merico |first11=Agostino |date=2020 |title=Extinction and dawn of the modern world in the Carnian (Late Triassic) |journal=Science Advances |volume=6 |issue=38 |pages=eaba0099 |doi=10.1126/sciadv.aba0099 |pmc=7494334 |pmid=32938682|bibcode=2020SciA....6...99D }}</ref> Another extinction occurred at the Carnian-Norian boundary, ending the Carnian age.<ref>{{cite journal |last1=Onoue |first1=Tetsuji |last2=Zonneveld |first2=John-Paul |last3=Orchard |first3=Michael J. |last4=Yamashita |first4=Misa |last5=Yamashita |first5=Katsuyuki |last6=Sato |first6=Honami |last7=Kusaka |first7=Soichiro |date=1 January 2016 |title=Paleoenvironmental changes across the Carnian/Norian boundary in the Black Bear Ridge section, British Columbia, Canada |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018215005702 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=441 |pages=721–733 |doi=10.1016/j.palaeo.2015.10.008 |bibcode=2016PPP...441..721O |access-date=24 January 2023}}</ref>
== Stratigraphic definitions ==
[[File:Trachyceras Brotheotrachyceras brotheus.jpg|thumb|right|''Brotheotrachyceras brotheus'' from the [[San Cassiano Formation]], [[Val Badia]], [[Dolomites]], [[Southern Alps (geology)|Southern Alps]]. This [[ammonite|ammonoid]] is an [[index fossil]] for the lower Carnian]]
The Carnian was named in 1869 by [[Johann August Georg Edmund Mojsisovics von Mojsvar|Mojsisovics]]. It is unclear if it was named after the [[Carnic Alps]] or after the Austrian region of [[Carinthia (state)|Carinthia]] (''Kärnten'' in German)<ref name="Gradstein_et-al_2012">{{cite book | title=The Geologic Timescale 2012 (volume 1) | publisher=Elsevier |veditors=Gradstein FM, Ogg JG, Schmitz MD, Ogg GM | year=2012 | page=687 | isbn=978-0-44-459390-0}}</ref> or after the [[Carnia]] historical region in northeastern Italy.{{Citation needed|date=May 2018}} The name, however, was first used referring to a part of the [[Hallstatt Limestone]] [[Outcrop|cropping out]] in [[Austria]].<ref name="Gradstein_et-al_2012"/>
The base of the Carnian Stage is defined as the place in the stratigraphic record where the [[ammonite]] species ''[[Daxatina|Daxatina canadensis]]'' first appears. The global reference profile for the base is located at the ''Stuores-Wiesen'' near [[Badia, South Tyrol|Badia]] in the [[Val Badia]] in the region of [[South Tyrol]], [[Italy]].<ref>The GSSP was firstly proposed by Broglio Loriga ''et al.'' (1999) and established by Mietto ''et al.'' (2012)</ref>
The top of the Carnian (the base of the Norian) is at the bases of the ammonite [[biozone]]s of ''[[Klamathites|Klamathites macrolobatus]]'' or ''[[Stikinoceras|Stikinoceras kerri]]'' and the [[conodont]] biozones of ''[[Metapolygnathus|Metapolygnathus communisti]]'' or ''[[Metapolygnathus|Metapolygnathus primitius]]''.
=== Subdivisions ===
There is no established, standard usage for the Carnian subdivisions, thus, while in some regional stratigraphies a two-substage subdivision is common:
* Julian
* Tuvalian
others prefer a three-substage organization of the stage as follows:
* Cordevolian
* Julian
* Tuvalian
=== Biostratigraphy ===
In the [[Tethys Ocean|Tethys domain]], the Carnian Stage contains six ammonite biozones:
* zone of ''[[Anatropites|Anatropites spinosus]]''
* zone of ''[[Tropites|Tropites subbullatus]]''
* zone of ''[[Tropites|Tropites dilleri]]''
* zone of ''[[Austrotrachyceras|Austrotrachyceras austriacum]]''
* zone of ''[[Trachyceras]]''
The '''Otischalkian''' land vertebrate [[faunachron]] corresponds to the early late Carnian, while the '''Adamanian''' land vertebrate [[faunachron]] corresponds to the latest Carnian.<ref>{{cite journal |last1=Heckert |first1=A.B. |year=2004 |title=Late Triassic microvertebrates from the lower Chinle Group (Otischalkian-Adamanian: Carnian), southwestern USA |journal=New Mexico Museum of Natural History and Science Bulletin |volume=27 |url=https://books.google.com/books?id=T2cfCgAAQBAJ&dq=adamanian&pg=PP1 |access-date=17 November 2021 |page=1}}</ref>
== Paleogeography and climate ==
[[File:CARNIAN EARTH.jpg|thumb|right|Carnian Earth]]
The paleogeography of the Carnian was basically the same as for the rest of the Triassic. Most continents were merged into the supercontinent [[Pangaea]], and there was a single global ocean, [[Panthalassa]]. The global ocean had a western branch at tropical latitudes called [[Paleo-Tethys Ocean|Paleo-Tethys]]. The sediments of Paleo-Tethys now crop out in southeastern [[Europe]], in the [[Middle East]], in the [[Himalayas]], and up to the [[Timor|island of Timor]].
The extreme land-sea distribution led to "mega-monsoons", i.e., an atmospheric [[monsoon|monsoon regime]] more intense than the present one.
As for most of the Mesozoic, there were no ice caps. Climate was mostly arid in the tropics, but an episode of wet tropical climate is documented at least in the Paleo-Tethys. This putative climatic event is called the "[[Carnian Pluvial Event]]", its age being between latest early Carnian (Julian) and the beginning of late Carnian (Tuvalian).
== Carnian life ==
{{main|:Category:Carnian life}}
In the marine realm, the Carnian saw the first abundant occurrences of calcareous nanoplankton, a morphological group including the [[coccolithophore]]s.
=== Invertebrates ===
There are a few invertebrates which are typical and characteristic of the Carnian. Among molluscs, the [[ammonite|ammonoid]] genus ''Trachyceras'' is exclusive to the lower Carnian (i.e., Julian of the two-substages subdivision, see above). The family Tropitidae and the genus ''Tropites'' appear at the base of the upper Carnian (Tuvalian). The [[bivalvia|bivalve]] genus ''Halobia'', a bottom-dweller of deep sea environments, differentiated from ''[[Daonella]]'' at the beginning of this age. [[Scleractinia]]n coral reefs, i.e., reefs with corals of the modern type, became relatively common for the first time in the Carnian.
=== Vertebrates ===
The earliest unequivocal [[dinosaur|dinosaurs]], such as those from the Ischigualato Formation (e.g. ''[[Herrerasaurus]]'' and ''[[Eoraptor]]'') and those from the [[Santa Maria Formation]] (e.g. ''[[Staurikosaurus]]'' and ''[[Buriolestes]]'') originated during the Carnian, around 230 [[Myr|Ma]].
In this stage the [[archosaur]]s became the dominant faunas in the world, evolving into groups such as the [[phytosaur]]s, [[rhynchosaur]]s, [[aetosaur]]s, and [[rauisuchia]]ns. The first dinosaurs (and the pterosaur [[Carniadactylus]]) also appeared in this stage, and though at the time they were small and insignificant, they diversified rapidly and would dominate the fauna for the rest of the [[Mesozoic]]. On the other hand, the [[therapsid]]s, which included the ancestors of [[mammal]]s, decreased in both size and diversity, and would remain relatively small until the extinction of the dinosaurs.
[[Conodont]]s were present in Triassic marine sediments. ''[[Paragondolella|Paragondolella polygnathiformis]]'' appeared at the base of the Carnian Stage, and is considered a characteristic species. A partial list of Carnian vertebrates is given below. Many Carnian vertebrates are found in [[Santa Maria Formation]] rocks of the Paleorrota [[geopark]].
== Classic localities and Lagerstätten ==
The lower Carnian fauna of the [[San Cassiano Formation]] ([[Dolomites]], northern [[Italy]]) has been studied since the 19th century. Fossiliferous localities are many, and are distributed mostly in the surroundings of [[Cortina d'Ampezzo]] and in the high Badia Valley, near the village of [[San Cassiano]], after which the formation was named. This fauna is extremely diverse, including ammonoids, gastropods, bivalves, echinoderms, [[calcareous sponge]], corals, [[brachiopod]]s, and a variety of less common fossils. A collection of this fauna is exposed in the "Museo delle Regole", a museum in Cortina d'Ampezzo.
The [[Ischigualasto Formation]] of the [[Ischigualasto-Villa Unión Basin]] in northwestern Argentina yielded a very important vertebrate association, including the oldest dinosaurian assemblage.
The Lagerstätte of the [[Madygen Formation]] in Kyrgyzstan has provided over 20,000 fossil insects, vertebrates and flora.
=== Notable Formations ===
* [[Chañares Formation]] (Argentina)
* [[Denmark Hill Insect Bed]] (Queensland, Australia)
* [[Ischigualasto Formation]] (Argentina)
* [[Los Rastros Formation]] (Argentina)
* [[Molteno Formation]] (South Africa)
* [[Potrerillos Formation, Argentina|Potrerillos Formation]] (Argentina)
* [[Santa Maria Formation]] (Rio Grande do Sul, Brazil)
* [[Stuttgart Formation]] (Germany)
* [[Xiaowa Formation]] / Wayao Member of the Falang Formation ([[Guizhou]] and [[Yunnan]], China)
* [[Zhuganpo Formation]] / Zhuganpo Member of the Falang Formation (late Ladinian - early Carnian) (Guizhou and Yunnan, China)
== References ==
{{reflist}}
=== Bibliography ===
* {{aut|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.&nbsp;233–244.
* {{aut|Broglio Loriga, C.; Cirilli, S.; De Zanche, V.; Di Bari, D.; Gianolla, P.; Laghi, G.; Manfrin, S.; Mastandrea, A.; Mietto, P.; Muttoni, G.; Neri, C.; Posenato, R.; Rechichi, M.C.; Rettori R. & Roghi, G.}}; '''1999''': ''The Prati di Stuores/Stuores Wiesen section (Dolomites, Italy): a candidate Global Stratotype section and Point for the base of the Carnian stage'', Rivista Italiana di Paleontologia e Stratigrafia '''105''', pp.&nbsp;37–78.
* {{aut|Furin, S.; Preto, N.; Rigo, M.; Roghi, G.; Gianolla, P.; Crowley, J.L. & Bowring, S.A.}}; '''2006''': ''High-precision U-Pb zircon age from the Triassic of Italy: Implications for the Triassic time scale and the Carnian origin of calcareous nannoplankton and dinosaurs'', Geology '''34''', p.&nbsp;1009–1012.
* {{aut|Gradstein, F.M.; Ogg, J.G. & Smith, A.G.}}; '''2004''': ''A Geologic Time Scale 2004'', [[Cambridge University Press]].
* {{aut|Gradstein, F.M.; Ogg, J.G., Schmitz, M.D. & Ogg, G.M.}}; '''2012''': ''The Geologic Time Scale 2012'', [[Elsevier]].
* {{aut|Lucas, S.G.; Luo, Zhe-Xi}}; '''1993''': ''Adelobasileus from the upper Triassic of west Texas: the oldest mammal'', J. Vert. Paleont. '''13''', pp.&nbsp;309–334.
* {{aut|Mietto, P.; Manfrin, S.; Preto, N.; Rigo, M.; Roghi, G.; Furin, S.; Gianolla, P.; Posenato, R.; Muttoni, G.; Nicora, A.; Buratti, N.; Cirilli, S.; Spoetl, C.; Ramezani, J. & Bowring, S.A.}}; '''2012''': ''The Global Boundary Stratotype Section and Point (GSSP) of the Carnian stage (Late Triassic) at Prati di Stuores/Stuores Wiesen section (Southern Alps, NE Italy)'', Episodes '''35''', pp.&nbsp;414–430.
== External links ==
* [https://web.archive.org/web/20100823100613/http://www.stratigraphy.org/bak/geowhen/stages/Carnian.html GeoWhen Database – Carnian]
* [http://stratigraphy.science.purdue.edu/charts/Timeslices/7_Upper_Trias.pdf 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'', [https://web.archive.org/web/20060518100851/http://norges.uio.no/timescale/Late_Triassic.pdf], [https://web.archive.org/web/20051109154300/http://norges.uio.no/timescale/Fig16.1_Tri_colA.pdf] and [https://web.archive.org/web/20060518101406/http://norges.uio.no/timescale/Fig16.1_Tri_colB.pdf]
* [https://web.archive.org/web/20060221052032/http://www.palaeos.com/Mesozoic/Triassic/Carnian.htm Palaeos Mesozoic: Carnian Age]
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