The Carnian (less commonly, Karnian) is the lowermost
stage
Stage or stages may refer to:
Acting
* Stage (theatre), a space for the performance of theatrical productions
* Theatre, a branch of the performing arts, often referred to as "the stage"
* ''The Stage'', a weekly British theatre newspaper
* Sta ...
of the Upper
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
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 in ...
(or earliest
age
Age or AGE may refer to:
Time and its effects
* Age, the amount of time someone or something has been alive or 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 by ...
). It lasted from 237 to 227
million years ago (Ma). The Carnian is preceded by the
Ladinian
The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic ...
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
The Carnian pluvial episode (CPE), often called the Carnian pluvial event, was an interval of major change in Climate change (general concept), global climate synchronous with significant changes in Earth's biota both in the sea and on land. It o ...
characterized by substantial rainfall) occurred during the Carnian and seems to be associated with important extinctions or biotic radiations.
Stratigraphic definitions
![Trachyceras Brotheotrachyceras brotheus](https://upload.wikimedia.org/wikipedia/commons/5/59/Trachyceras_Brotheotrachyceras_brotheus.jpg)
The Carnian was named in 1869 by
Mojsisovics. It is unclear if it was named after the
Carnic Alps
The Carnic Alps ( it, Alpi Carniche; german: Karnische Alpen; sl, Karnijske Alpe; fur, Alps Cjargnelis) are a range of the Southern Limestone Alps in Austria and northeastern Italy. They are within Austrian East Tyrol and Carinthia, and Itali ...
or after the Austrian region of
Carinthia (''Kärnten'' in German)
or after the
Carnia historical region in northwestern Italy. The name, however, was first used referring to a part of the
Hallstatt Limestone
Hallstatt ( , , ) is a small town in the district of Gmunden, in the Austrian state of Upper Austria. Situated between the southwestern shore of Hallstätter See and the steep slopes of the Dachstein massif, the town lies in the Salzkammergut ...
cropping out in
Austria
Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...
.
The base of the Carnian Stage is defined as the place in the stratigraphic record where the
ammonite species ''
Daxatina canadensis
''Daxatina'' is a fossil ammonoid cephalopod included in the trachyceratid family of the order Ceratitida that lived during the middle of the Triassic.
Distribution
Triassic of Canada, Italy, Svalbard, Jan Mayen and Alaska
References
;Notes ...
'' first appears. The global reference profile for the base is located at the ''Stuores-Wiesen'' near
Badia in the
Val Badia
The Val Badia ( en, Badia Valley, Ladin: ''Val Badia''; it, Val Badia; german: Gadertal) is the valley of the Gran Ega river in South Tyrol, Italy. It stretches from the Sella massif northwards to the Puster Valley. The villages in the Val Badia ...
in the region of
South Tyrol
it, Provincia Autonoma di Bolzano – Alto Adige lld, Provinzia Autonoma de Balsan/Bulsan – Südtirol
, settlement_type = Autonomous area, Autonomous Provinces of Italy, province
, image_skyline = ...
,
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
.
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 taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties ...
s 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
''Trachyceras'' is a genus belonging to the extinct subclass of cephalopods known as ammonites. Specifically it belongs in the order Ceratitida
Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as we ...
''
The Otischalkian land vertebrate
faunochron corresponds to the early late Carnian, while the Adamanian land vertebrate
faunochron corresponds to the latest Carnian.
Paleogeography and climate
![CARNIAN EARTH](https://upload.wikimedia.org/wikipedia/commons/4/4e/CARNIAN_EARTH.jpg)
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 approximately 335 million y ...
, 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 superocean that surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During th ...
. The global ocean had a western branch at tropical latitudes called
Paleo-Tethys
The Paleo-Tethys or Palaeo-Tethys Ocean was an ocean located along the northern margin of the paleocontinent Gondwana that started to open during the Middle Cambrian, grew throughout the Paleozoic, and finally closed during the Late Triassic; ex ...
. The sediments of Paleo-Tethys now crop out in southeastern
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
, in the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
, 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 planet's highest peaks, including the very highest, Mount Everest. Over 10 ...
, 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 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 king ...
s.
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
''Daonella'' is a genus of oyster-like saltwater clams, marine bivalve mollusks which lived in the middle to late Triassic period. They are related to the genera '' Aparimella'' and '' Halobia''. Since they were ubiquitous in the Arctic, Tethy ...
'' 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 ...
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, such as those from the Ischigualato Formation (e.g. ''
Herrerasaurus
''Herrerasaurus'' is a genus of saurischian dinosaur from the Late Triassic period. This genus was one of the earliest dinosaurs from the fossil record. Its name means "Herrera's lizard", after the rancher who discovered the first specimen in ...
'' and ''
Eoraptor
''Eoraptor'' () is a genus of small, lightly built, basal sauropodomorph. One of the earliest-known dinosaurs, it lived approximately 231 to 228 million years ago, during the Late Triassic in Western Gondwana, in the region that is now northwes ...
'') and those from the
Santa Maria Formation
The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age (Late Triassic), and is notable for its fossils of cynodonts, "rauisuchian" pseudosuchians, and early dinosaurs and other ...
(e.g. ''
Staurikosaurus'' and ''
Buriolestes
''Buriolestes'' is a genus of early sauropodomorph dinosaurs from the Late Triassic Santa Maria Formation of the Paraná Basin in southern Brazil. It contains a single species, ''B. schultzi'', named in 2016. The type specimen was found alongsid ...
'') originated during the Carnian, around 230
Ma.
In this stage the
archosaurs became the dominant faunas in the world, evolving into groups such as the
phytosaur
Phytosaurs (Φυτόσαυροι in greek) are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria. Phytosauria and Phytosauridae are often considered to be equivalent g ...
s,
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 ...
s,
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, herbivoro ...
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
''Carniadactylus'' is a genus of pterosaur which existed in Europe during the Late Triassic period (late Carnian or early Norian, about 228 million years agoBarrett, P. M., Butler, R. J., Edwards, N. P., & Milner, A. R. (2008). Pterosaur distribu ...
) 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 ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...
. On the other hand, the
therapsid
Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...
s, 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
The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age (Late Triassic), and is notable for its fossils of cynodonts, "rauisuchian" pseudosuchians, and early dinosaurs and other ...
rocks of the Paleorrota
geopark
A geopark is a protected area with internationally significant geology within which sustainable development is sought and which includes tourism, conservation, education and research concerning not just geology but other relevant sciences.
In 2 ...
.
Classic localities and Lagerstätten
The lower Carnian fauna of the
San Cassiano Formation (
Dolomites
The Dolomites ( it, Dolomiti ; Ladin: ''Dolomites''; german: Dolomiten ; vec, Dołomiti : fur, Dolomitis), also known as the Dolomite Mountains, Dolomite Alps or Dolomitic Alps, are a mountain range located in northeastern Italy. They form pa ...
, northern
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
) 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
San Cassiano is a town and ''comune'' in the Italian province of Lecce and region of Apulia in south-east Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is lo ...
, after which the formation was named. This fauna is extremely diverse, including ammonoids, gastropods, bivalves, echinoderms,
calcareous sponge, corals,
brachiopod
Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan 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 end, w ...
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
The Ischigualasto Formation is a Late Triassic fossiliferous formation and Lagerstätte in the Ischigualasto-Villa Unión Basin of the southwestern La Rioja Province and northeastern San Juan Province in northwestern Argentina. The formation ...
of the
Ischigualasto-Villa Unión Basin
The Ischigualasto-Villa Unión Basin ( es, Cuenca de Ischigualasto-Villa Unión) is a small sedimentary basin located in the Argentine Northwest, Argentina. It is located in the southwestern part of La Rioja Province and the northeastern part of ...
in northwestern Argentina yielded a very important vertebrate association, including the oldest dinosaurian assemblage.
The Lagerstätte of the
Madygen Formation
The Madygen Formation ( Russian: Madygen Svita) is a Late Triassic (Carnian) geologic formation and Lagerstätte in the Batken and Osh Regions of western Kyrgyzstan, with minor outcrops in neighboring Tajikistan and Uzbekistan. The conglomerates, ...
in Kyrgyzstan has provided over 20,000 fossil insects, vertebrates and flora.
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 is the university press of the University of Cambridge. Granted letters patent by King Henry VIII in 1534, it is the oldest university press in the world. It is also the King's Printer.
Cambridge University Pre ...
.
* ; 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'', the ScienceDirect collection of electronic journals, '' Trends'', ...
.
* ; 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 – CarnianUpper 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