The Carnian (less commonly, Karnian) is the lowermost stage of the Upper

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

Series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used i ...

(or earliest

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

of the Late Triassic

Epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

). It lasted from 237 to 227.3 million years ago (Ma). The Carnian is preceded by the Ladinian and is followed by the

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

. 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. Another extinction occurred at the Carnian-Norian boundary, ending the Carnian age.

Stratigraphic definitions

The Carnian was named in 1869 by Mojsisovics. It is unclear if it was named after the

Carnic Alps The Carnic Alps (; ; ; ) are a range of the Southern Limestone Alps in Austria and northeastern Italy. They are within Austrian East Tyrol and Carinthia, and Italian Friuli (Province of Udine) and marginally in Veneto. Etymology They are ...

or after the Austrian region of

Carinthia Carinthia ( ; ; ) is the southernmost and least densely populated States of Austria, Austrian state, in the Eastern Alps, and is noted for its mountains and lakes. The Lake Wolayer is a mountain lake on the Carinthian side of the Carnic Main ...

(''Kärnten'' in German) or after the Carnia historical region in northeastern Italy. The name, however, was first used referring to a part of the Hallstatt Limestone cropping out in

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

. The base of the Carnian Stage is defined as the place in the stratigraphic record where the

ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

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 South Tyrol ( , ; ; ), officially the Autonomous Province of Bolzano – South Tyrol, is an autonomous administrative division, autonomous provinces of Italy, province in northern Italy. Together with Trentino, South Tyrol forms the autonomo ...

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

. The top of the Carnian (the base of the Norian) is at the bases of the ammonite

biozone In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxon, taxa, as opposed to a Lithostratigraphy, lithostratigraphic unit which is defined by the ...

s of '' Klamathites macrolobatus'' or '' Stikinoceras kerri'' and the

conodont Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...

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'' The Otischalkian land vertebrate faunachron corresponds to the early late Carnian, while the Adamanian land vertebrate faunachron corresponds to the latest Carnian.

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 Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous period approximately 335 mi ...

, and there was a single global ocean,

Panthalassa Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek "all" and "sea"), was the vast superocean that encompassed planet Earth and surrounded the supercontinent Pangaea, the latest in a series of supercontinent ...

. The global ocean had a western branch at tropical latitudes called Paleo-Tethys. The sediments of Paleo-Tethys now crop out in southeastern

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, in the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

, in the

Himalayas The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of h ...

, 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 The Carnian pluvial episode (CPE), often called the Carnian pluvial event, was a period of major change in global climate that coincided with significant changes in Earth's biota both in the sea and on land. It occurred during the latter part of ...

", 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 nanoplankton, a morphological group including the

coccolithophore Coccolithophores, or coccolithophorids, are single-celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the kingdom ...

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 Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

genus ''Halobia'', a bottom-dweller of deep sea environments, differentiated from '' Daonella'' at the beginning of this age.

Scleractinia Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mo ...

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

dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

, such as those from the Ischigualasto Formation (e.g. '' Herrerasaurus'' and ''

Eoraptor ''Eoraptor'' () is a genus of small, lightly built, Basal (phylogenetics), basal sauropodomorpha, sauropodomorph dinosaur. One of the earliest-known dinosaurs and one of the earliest sauropodomorphs, it lived approximately 231 to 228 million yea ...

'') and those from the Santa Maria Formation (e.g. '' Staurikosaurus'' and '' Buriolestes'') originated during the Carnian, around 230 Ma. In this stage the

archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...

s became the dominant faunas in the world, evolving into groups such as the phytosaurs,

rhynchosaur Rhynchosaurs are a group of extinct herbivorous Triassic archosauromorph reptiles, belonging to the order Rhynchosauria. Members of the group are distinguished by their triangular skulls and elongated, beak like premaxillary bones. Rhynchosaurs ...

aetosaur Aetosaurs () are heavily armored reptiles belonging to the extinct order (biology), order Aetosauria (; from Ancient Greek, Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized Omnivore, omnivorous or Herbivore, herbivor ...

s, and

rauisuchia "Rauisuchia" is a paraphyletic group of mostly large and carnivorous Triassic archosaurs. Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilians ...

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 The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

. On the other hand, the therapsids, which included the ancestors of

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s, decreased in both size and diversity, and would remain relatively small until the extinction of the dinosaurs.

Conodont Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...

s 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 A geopark is a protected area with internationally significant geology within which Sustainability, sustainable development is sought and which includes tourism, conservation, education and research concerning not just geology but other relevant s ...

Classic localities and Lagerstätten

The lower Carnian fauna of the San Cassiano Formation (

Dolomites The Dolomites ( ), also known as the Dolomite Mountains, Dolomite Alps or Dolomitic Alps, are a mountain range in northeastern Italy. They form part of the Southern Limestone Alps and extend from the River Adige in the west to the Piave Va ...

, northern

) has been studied since the 19th century. Fossiliferous localities are many, and are distributed mostly in the surroundings of

Cortina d'Ampezzo Cortina d'Ampezzo (; , ; historical ) sometimes abbreviated to simply Cortina, is a town and ''comune'' in the heart of the southern (Dolomites, Dolomitic) Alps in the province of Belluno, in the Veneto region of Northern Italy. Situated on the ...

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 Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

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) * Santa Maria Formation (Rio Grande do Sul, Brazil) * Stuttgart Formation (Germany) * Xiaowa Formation / Wayao Member of the Falang Formation (

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and

Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

, China) * Zhuganpo Formation / Zhuganpo Member of the Falang Formation (late Ladinian - early Carnian) (Guizhou and Yunnan, China)

References

Bibliography

* ; 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. * ; 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. * ; 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. * ; 2004: ''A Geologic Time Scale 2004'',

Cambridge University Press Cambridge University Press was the university press of the University of Cambridge. Granted a letters patent by King Henry VIII in 1534, it was the oldest university press in the world. Cambridge University Press merged with Cambridge Assessme ...

. * ; 2012: ''The Geologic Time Scale 2012'',

Elsevier Elsevier ( ) is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as ''The Lancet'', ''Cell (journal), Cell'', the ScienceDirect collection of electronic journals, ...

. * ; 1993: ''Adelobasileus from the upper Triassic of west Texas: the oldest mammal'', J. Vert. Paleont. 13, pp. 309–334. * ; 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''

an

Palaeos Mesozoic: Carnian Age
{{Portal bar, Geology, Paleontology Carnian, *01 Geological ages Triassic geochronology