Carnian
The Carnian (less commonly, Karnian) is the lowermost stage of the Upper Triassic series (or earliest age of the Late Triassic epoch). It lasted from 237 to 227 million years ago (Ma).[7] 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 Event) occurred during the Carnian and seems to be associated with important extinctions or biotic radiations.
| Carnian | |
|---|---|
| ~237 – ~227 Ma | |
 | |
| Chronology | |
Key events in the Triassic -255 — – -250 — – -245 — – -240 — – -235 — – -230 — – -225 — – -220 — – -215 — – -210 — – -205 — – -200 — An approximate timescale of key Triassic events. Axis scale: millions of years ago. (NOTE: The white links are for readability only. They are still clickable.) | |
| Etymology | |
| Name formality | Formal |
| Alternate spelling(s) | Karnian |
| 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 | FAD of the Ammonite Daxatina canadensis |
| Lower boundary GSSP | Prati di Stuores, Dolomites, Italy 46.5269°N 11.9303°E |
| GSSP ratified | 2008[5] |
| Upper boundary definition | Not formally defined[6] |
| Upper boundary definition candidates | Base of Stikinoceras kerri ammonoid zone and near FAD of Metapolygnathus echinatus within the M. communisti conodont zones[6] |
| Upper boundary GSSP candidate section(s) |
|
Stratigraphic definitions
The Carnian was named in 1869 by Mojsisovics. It is unclear if it was named after the Carnic Alps or after the Austrian region of Carinthia (Kärnten in German)[8] or after the Carnia historical region in northwestern Italy. The name, however, was first used referring to a part of the Hallstatt Limestone cropping out in Austria.[8]
The base of the Carnian stage is defined as the place in the stratigraphic record where the ammonite species Daxatina canadensis first appears. The global reference profile for the base is located at the Stuores-Wiesen near Badia in the Val Badia in the region of South Tyrol, Italy.[9]
The top of the Carnian (the base of the Norian) is at the bases of the ammonite biozones of Klamathites macrolobatus or Stikinoceras kerri and the conodont biozones of Metapolygnathus communisti or 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 domain, the Carnian stage contains six ammonite biozones:
- zone of Anatropites spinosus
- zone of Tropites subbullatus
- zone of Tropites dilleri
- zone of Austrotrachyceras austriacum
- zone of Trachyceras
Paleogeography and climate
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. The sediments of Paleo-Tethys now crop out in southeastern Europe, in the Middle East, in the Himalayas, and up to the island of Timor. The extreme land-sea distribution led to "mega-monsoons", i.e., an atmospheric 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
In the marine realm, the Carnian saw the first abundant occurrences of calcareous nannoplankton, a morphological group including the coccolithophores.
Invertebrates
There are a few invertebrates which are typical and characteristic of the Carnian. Among molluscs, the 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 bivalve genus Halobia, a bottom-dweller of deep sea environments, differentiated from Daonella at the beginning of this age. Scleractinian coral reefs, i.e., reefs with corals of the modern type, became relatively common for the first time in the Carnian.
Vertebrates
The earliest dinosaurs, such as Herrerasaurus and Eoraptor originated during the Carnian, around 230 Ma. The oldest well documented dinosaurian assemblage, in the Ischigualasto Formation of Argentina, is most probably late Carnian in age.
In this stage the archosaurs became the dominant faunas in the world, evolving into groups such as the phytosaurs, rhynchosaurs, aetosaurs, and rauisuchians. 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 therapsids, which included the ancestors of mammals, decreased in both size and diversity, and would remain relatively small until the extinction of the dinosaurs.
Conodonts were present in Triassic marine sediments. 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.
Chondrichthyans
| Chondrichthyes of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
|
Triassic | England, Germany, India | An xenacanth elasmobranch |
 Mooreodontus |
Actinopterygians
| Actinopterygii of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Triassic | China, Slovenia, Italy | A non-neopterygian |
| |
| Anisian to Carnian | England, Morocco | A perleidiform | ||
| Late Triassic | United States | A redfieldiiform non-neopterygian | ||
| Late Triassic | United States | A teleosteomorph (modern ray-fin) | ||
| Late Triassic | Switzerland | A neopterygian | ||
| Middle Triassic to Late Triassic | Austria | A teleosteomorph (modern ray-fin) | ||
| Middle Triassic to Early Jurassic | Italy | A non-neopterygian | ||
| Triassic | China, Italy | A non-neopterygian | ||
| Late Triassic | Germany | A neopterygian | ||
| Middle Triassic to Late Triassic | Austria, Italy | The earliest gliding fish | ||
Coelacanths
| Actinistia of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Late Triassic | United States | A mawsoniid coelacanth |
| |
| Late Triassic to Jurassic | United States | A mawsoniid coelacanth | ||
| Middle Triassic | Austria | A coelacanth | ||
Temnospondyls
| Temnospondyls of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Argana Basin, High Atlas, Morocco |
| |||
|
|
|||
| Carnian - Norian | Southern Brazil | |||
| Australia | ||||
| Argana Basin, High Atlas, Morocco | ||||
| All across the US and India | ||||
| Europe and North America | ||||
| Northwestern Argentina | ||||
†Chroniosuchians
| Chroniosuchia of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Late Triassic | Madygen Formation, Kyrgyzstan | A stem tetrapod |
| |
†Procolophonomorphs
| Procolophonomorpha of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Late Triassic | Scotland | A genus of lizard-shaped parareptile |
| |
†Pachypleurosaurs
| Pachypleurosauria of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Middle Triassic | China | A sauropterygian |
| |
†Pistosaurs
| Pistosauria of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Middle Triassic | Italy | A sauropterygian |
| |
| Late Triassic | China | A sauropterygian | ||
†Placodonts
| Placodonts of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Early Carnian |
| |||
| Late Triassic | Spain | |||
| Late Triassic | China | |||
| Tuvalian | China | |||
†Thalattosaurs
| Thalattosauria of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Middle Triassic to Late Triassic | China |
 Nectosaurus (left) and Thalattosaurus (right) | ||
| Late Triassic | China | |||
| Late Triassic | Falang Formation, Guizhou, China | A relatively large thalattosaurian, more than 4 metres (13 ft) long | ||
| Late Triassic | United States | |||
| Middle Triassic to Late Triassic | United States | |||
| Middle Triassic to Late Triassic | China | |||
†Ichthyosaurs
| Ichthyosaurs of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
|
| ||||
| An elongate ichthyosaur | ||||
| A large ichthyosaur | ||||
| A large ichthyosaur | ||||
†Archosauromorphs and Archosauriformes (non-archosaurian)
| Non-Archosaurian Archosauromorphs of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Doswell Formation, Virginia | Doswellia was a low and heavily built carnivore. |
| ||
| Middle Triassic to Late Triassic | Chañares Formation, Argentina | A genus of modest sized proterochampsid. | ||
| Middle Triassic to Late Triassic | Chañares Formation, Argentina | A genus of proterochampsid archosauriform. | ||
|
Europe:
India:
South America:
|
One of the most derived genera of rhynchosaurs and the most widespread and diverse with at least six verified species from Europe, Asia and South America and potentially more species from Africa and North America. | ||
| Makay Formation, Madagascar | A derived rhynchosaur and a very close relative of Hyperodapedon, possibly a species in that genus. | |||
| late Carnian | Lower Dockum Group, Texas | A genus of dubious hyperodapedontind rhynchosaurs. | ||
| Middle Triassic to Late Triassic | Madygen Formation, Kyrgyzstan | Archosauromorph with elongate integumentary appendages | ||
| late Carnian | Krasiejów quarry, Poland | A genus of gliding reptile closely related to Sharovipteryx. A recent phylogenetic analysis incorporating Ozimek found it as a member of the Tanystropheidae, as a close relative of Langobardisaurus and Tanytrachelos. This may suggest that both Ozimek and Sharovipteryx are members of the clade. | ||
| Santa Maria Formation, Argentina | A genus of proterochampsid. | |||
| 229 Ma | Ischigualasto Formation, Argentina | A genus of proterochampsid originally thought as a species of Chanaresuchus. | ||
| Calcare del Predil Formation, Italy | A tanystropheid. | |||
| late Carnian — earliest Norian | Santa Maria Formation, Argentina | A genus of proterochampsid. | ||
| A tanystropheid. | ||||
| Solite Quarry. Cascade, Virginia | A tanystropheid. | |||
| A herbivorous lizard-like allokotosaur that reached up to 2.5 m long. | ||||
| Middle Triassic to Late Triassic | Chañares Formation, Argentina | A genus of proterochampsid archosauriform. | ||
| All across Europe | Zanclodon is the name formally used for fossil material that might actually belongs to at least two genera of dinosaur from the Late Triassic among other genera. | |||
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†Pseudosuchians (non-crocodylomorphan, non-aetosaurian)
| †Non-crocodylomorph, non-aetosaurian Crurotarsans of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
|
| ||||
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†Aetosaurs
| †Aetosaurs of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
|
| ||||
Crocodylomorphs
| Crocodylomorphs of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
|
| ||||
| Late Carnian or early Norian | ||||
Avemetatarsalians (non-dinosaurian)
| †Avemetatarsalians of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Carnian - Norian | Timezgadiouine Formation, Argana Basin, Morocco | A silesaurid dinosauriform |
| |
| Ischigualasto Formation, Argentina | A silesaurid dinosauriform. | |||
| Santa Maria Formation, Rio Grande do Sul, Brazil | A lagerpetid dinosauromorph. | |||
| Ladinian - Carnian | Chañares Formation, La Rioja Province, Argentina | A lagerpetid dinosauromorph. | ||
| Ladinian - Carnian | Chañares Formation, La Rioja Province, Argentina | A basal dinosauromorph. | ||
| Ladinian - Carnian | Chañares Formation, La Rioja Province, Argentina | A basal dinosauriform. | ||
| Ischigualasto Formation, San Juan, Argentina | A small, lightly built herbivore approximately 1 metre (39 in) in length and 30 centimetres (12 in) in height. Considered to be either the oldest known ornithischian, or a silesaurid | |||
| Carnian - Norian | Lossiemouth Sandstone Formation, Scotland | A small dinosauriform. | ||
| Agudo, Rio Grande do Sul, Brazil | A silesaurid dinosauriform. | |||
| Lossiemouth Sandstone, Scotland | Likely a basal avemetatarsalian. Its taxonomic status is heavily disputed. | |||
| Silesia, Poland | A silesaurid dinosauriform, measuring over 2 meters long. | |||
Dinosauria
| †Dinosaurs of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Maleri Formation, Andhra Pradesh, India | A basal saurischian dinosaur |
| ||
| Disputed: considered Norian by some researchers | Lesotho | A sauropodomorph dinosaur. | ||
| Santa Maria Formation, Rio Grande do Sul, Brazil | A very basal sauropodomorph. Being somewhat similar to later Norian sauropodomorphs suggests it was transitional between them and sauropodomorphs of its time. | |||
| Santa Maria Formation, Rio Grande do Sul, Brazil | A very basal dinosaur, possibly the most basal sauropodomorph. | |||
| Tecovas Formation, Texas | possibly a synonym of Chindesaurus | |||
| Colorado City Formation, Texas, USA | A herrerasaurid dinosaur | |||
| Ischigualasto Formation, San Juan, Argentina | One of the most basal sauropodomorphs. | |||
| Ischigualasto-Villa Unión Basin, Argentine Northwest, Argentina | One of the earliest dinosaurs. Possibly the most basal theropod. | |||
| Ischigualasto Formation, Argentina | One of the earliest dinosaurs. Uncertain affinities. | |||
| Disputed: considered Norian by some researchers | Lesotho, South Africa, Zimbabwe | A large robust sauropodomorph, potentially up to 10 meters long. | ||
| Santa Maria Formation, Rio Grande do Sul, Brazil | A herrerasaurid dinosaur. | |||
| Paleorrota, Brazil | An early dinosaur of uncertain affinities, possibly a close relative of Saturnalia. | |||
| Argentina | A large herrerasaurid dinosaur. | |||
| Santa Maria Formation, Rio Grande do Sul, Brazil | Basal saurischian dinosaur of uncertain affinities. | |||
| Santa Maria Formation, Rio Grande do Sul, Brazil | One of the most basal sauropodomorphs. | |||
| Early Carnian | Ischigualasto Formation, San Juan, Argentina | One of the most basal sauropodomorphs. | ||
| Paleorrota, Rio Grande do Sul, Brazil | May have been a primitive sauropodomorph, probably grew to about 1.5 metres (4.9 ft) long | |||
| Ischigualasto Formation, San Juan, Argentina | A herrerasaurid dinosaur. | |||
| Middle Carnian | Paleorrota, Rio Grande do Sul, Brazil | One of the first dinosaurs from the Carnian to be discovered. A herrerasaurid. | ||
| Santa Maria Formation, Brazil | Possible synonym of Staurikosaurus. | |||
Lepidosaurs
| Lepidosauria of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Late Triassic | Scotland | a rhynchocephalian |
| |
†Therapsids (non-mammalian)
| †Non-mammalian Therapsids of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Description | Images |
| Ischigualasto Formation, Argentina Paleorrota, Brazil |
| |||
| Chinle Formation, Arizona | ||||
Mammalia
| Mammalia of the Carnian | ||||
|---|---|---|---|---|
| Taxa | Presence | Location | Discussion | Images |
| Tecovas Formation, Palo Duro Canyon, Texas, USA | Some writers consider Adelobasileus to be a mammal,[10] while those who limit Mammalia to the crown group do not include this genus. In any case, Adelobasileus is thought to be either the common ancestor of all modern mammals or else a close relative of that ancestor. |
| ||
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, brachiopods, 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.
References
- Widmann, Philipp; Bucher, Hugo; Leu, Marc; Vennemann, Torsten; Bagherpour, Borhan; Schneebeli-Hermann, Elke; Goudemand, Nicolas; Schaltegger, Urs (2020). "Dynamics of the Largest Carbon Isotope Excursion During the Early Triassic Biotic Recovery". Frontiers in Earth Science. 8 (196): 1–16. 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.
- |note5-nudge-down=1 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. 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. doi:10.1126/science.1097023. PMID 15273391.
- Mietto, Paolo; Manfrin, Stefano; Preto, Nereo; Rigo, Manuel; Roghi, Guido; Furin, Stefano; Gianolla, Piero; Posenato, Renato; Muttoni, Giovanni; Nicora, Alda; Buratti, Nicoletta; Cirilli, Simonetta; Spötl, Christoph; Ramezani, Jahandar; Bowring, Samuel (September 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)" (PDF). Episodes. 35: 414–430. Retrieved 13 December 2020.
- "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 23 December 2020.
- https://stratigraphy.org/timescale/
- Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D.; Ogg, G.M. (editors) (2012). The Geologic Timescale 2012 (volume 1). Elsevier. p. 687. ISBN 978-0-44-459390-0.CS1 maint: multiple names: authors list (link) CS1 maint: extra text: authors list (link)
- The GSSP was firstly proposed by Broglio Loriga et al. (1999) and established by Mietto et al. (2012)
- Lucas and Luo (1993).
Bibliography
- 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.
- 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. 37–78.
- 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. 1009–1012.
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
- Gradstein, F.M.; Ogg, J.G., Schmitz, M.D. & Ogg, G.M.; 2012: The Geologic Time Scale 2012, Elsevier.
- Lucas, S.G.; Luo, Zhe-Xi; 1993: Adelobasileus from the upper Triassic of west Texas: the oldest mammal, J. Vert. Paleont. 13, pp. 309–334.
- 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. 414–430.
External links
- GeoWhen Database – Carnian
- 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, , and
- Palaeos Mesozoic: Carnian Age