Editing Triassic (section)

{{Short description|First period of the Mesozoic Era}}
{{Infobox geologic timespan
| name                         = {{Color|white|Triassic}}
| color                        = Triassic
| top_bar                      =
| time_start                   = 251.902
| time_start_uncertainty       = 0.024
| time_end                     = 201.4
| time_end_uncertainty         = 0.2
| image_map                    = Mollweide Paleographic Map of Earth, 225 Ma (Norian Age).png 
| caption_map                  = A map of Earth as it appeared during the [[Norian]] age of the [[Late Triassic]]
| image_outcrop                =
| caption_outcrop              =
| image_art                    =
| caption_art                  =
<!--Chronology-->  
| timeline                     = Triassic
<!--Etymology-->
| name_formality               = Formal
| name_accept_date             =
| alternate_spellings          =
| 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                  = Period
| strat_unit                   = System
| proposed_by                  =
| timespan_formality           = Formal
| lower_boundary_def           = First appearance of the [[conodont]] ''[[Hindeodus|Hindeodus parvus]]''
| lower_gssp_location          = [[Meishan]], [[Zhejiang]], [[China]]
| lower_gssp_coords            = {{Coord|31.0798|N|119.7058|E|display=inline}}
| lower_gssp_accept_date  = 2001<ref>{{cite journal |last1=Hongfu |first1=Yin |last2=Kexin |first2=Zhang |last3=Jinnan |first3=Tong |last4=Zunyi |first4=Yang |last5=Shunbao |first5=Wu |title=The Global Stratotype Section and Point (GSSP) of the Permian-Triassic Boundary |journal=Episodes |date=June 2001 |volume=24 |issue=2 |pages=102–114 |doi=10.18814/epiiugs/2001/v24i2/004 |url=https://stratigraphy.org/gssps/files/induan.pdf |access-date=8 December 2020 |doi-access=free}}</ref>
| upper_boundary_def   = First appearance of the [[ammonite]] ''[[Psiloceras|Psiloceras spelae tirolicum]]''
| upper_gssp_location   = Kuhjoch section, [[Karwendel|Karwendel mountains]], [[Northern Calcareous Alps]], Austria
| upper_gssp_coords   = {{Coord|47.4839|N|11.5306|E|display=inline}}
| upper_gssp_accept_date  = 2010<ref>{{cite journal |last1=Hillebrandt |first1=A.v. |last2=Krystyn |first2=L. |last3=Kürschner |first3=W. M. |last4=Bonis |first4=N. R. |last5=Ruhl |first5=M. |last6=Richoz |first6=S. |last7=Schobben |first7=M. A. N. |last8=Urlichs |first8=M. |last9=Bown |first9=P.R. |last10=Kment |first10=K. |last11=McRoberts |first11=C. A. |last12=Simms |first12=M. |last13=Tomãsových |first13=A. |display-authors=3 |title=The Global Stratotype Sections and Point (GSSP) for the base of the Jurassic System at Kuhjoch (Karwendel Mountains, Northern Calcareous Alps, Tyrol, Austria) |journal=Episodes |date=September 2013 |volume=36 |issue=3 |pages=162–198 |doi=10.18814/epiiugs/2013/v36i3/001 |doi-access=free |citeseerx=10.1.1.736.9905|s2cid=128552062 }}</ref>
<!--Atmospheric and Climatic Data-->
| sea_level                    =
}}
The '''Triassic''' ({{IPAc-en|t|r|aɪ|ˈ|æ|s|ɪ|k}} {{respell|try|ASS|ik}}; sometimes symbolized '''🝈''')<ref>{{dictionary.com|Triassic}}</ref> is a [[geologic period]] and [[system (stratigraphy)|system]] which spans 50.5 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 201.4 Mya.<ref name="StratChart 2023">{{cite web |title=International Stratigraphic Chart |url=https://stratigraphy.org/ICSchart/ChronostratChart2023-06.pdf |publisher=International Commission on Stratigraphy | date=June 2023 |access-date=19 July 2023}}</ref> The Triassic is the first and shortest period of the [[Mesozoic|Mesozoic Era]] and the seventh period of the [[Phanerozoic|Phanerozoic Eon]]. Both the start and end of the period are marked by major [[extinction event]]s.<ref name= "SahneyBenton2008RecoveryFromProfoundExtinction">{{cite journal |url= |author1=Sahney, S. |author2=Benton, M.J. |name-list-style=amp |year=2008 |title=Recovery from the most profound mass extinction of all time |journal=Proceedings of the Royal Society B: Biological Sciences |doi=10.1098/rspb.2007.1370 |volume=275 |pmid=18198148 |issue=1636 |pmc=2596898 |pages=759–765}}</ref> The Triassic Period is subdivided into three epochs: [[Early Triassic]], [[Middle Triassic]] and [[Late Triassic]].

The Triassic began in the wake of the [[Permian–Triassic extinction event]], which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the [[Mesozoic]] Era. 

[[Reptiles]], especially [[archosaur]]s, were the chief terrestrial vertebrates during this time. A specialized group of archosaurs, called [[dinosaur]]s, first appeared in the Late Triassic but did not become dominant until the succeeding Jurassic Period.<ref name="Brusatte">{{cite journal |last1=Brusatte |first1=S. L. |last2=Benton |first2=M. J. |last3=Ruta |first3=M. |last4=Lloyd |first4=G. T. |title=Superiority, Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs |journal=[[Science (journal)|Science]] |volume=321 |issue=5895 |pages=1485–1488 |date=2008-09-12 |url=http://palaeo.gly.bris.ac.uk/Benton/reprints/2008Science.pdf |doi=10.1126/science.1161833 |access-date=2012-01-14 |bibcode=2008Sci...321.1485B |pmid=18787166 |s2cid=13393888 |archive-url=https://web.archive.org/web/20140624204033/http://palaeo.gly.bris.ac.uk/Benton/reprints/2008Science.pdf |archive-date=2014-06-24 |hdl=20.500.11820/00556baf-6575-44d9-af39-bdd0b072ad2b |hdl-access=free}}</ref> Archosaurs that became dominant in this period were primarily [[pseudosuchia]]ns, relatives and ancestors of modern [[crocodilians]], while some archosaurs specialized in flight, the first time among vertebrates, becoming the [[pterosaurs]]. [[Therapsids]], the dominant vertebrates of the preceding Permian period, saw a brief surge in diversification in the Triassic, with [[Dicynodontia|dicynodonts]] and [[Cynodontia|cynodonts]] quickly becoming dominant, but they declined throughout the period with the majority becoming extinct by the end. However, the first stem-group [[mammal]]s ([[Mammaliamorpha|mammaliamorphs]]), themselves a specialized subgroup of cynodonts, appeared during the Triassic and would survive the extinction event, allowing them to radiate during the Jurassic. [[Amphibian|Amphibians]] were primarily represented by the [[Temnospondyli|temnospondyls]], giant aquatic predators that had survived the end-Permian extinction and saw a new burst of diversification in the Triassic, before going extinct by the end; however, early crown-group [[Lissamphibia|lissamphibians]] (including stem-group [[Frog|frogs]], [[Salamander|salamanders]] and [[Caecilian|caecilians]]) also became more common during the Triassic and survived the extinction event. The earliest known [[Neopterygii|neopterygian]] fish, including early [[Holostei|holosteans]] and [[Teleost|teleosts]], appeared near the beginning of the Triassic, and quickly diversified to become among the dominant groups of fish in both freshwater and marine habitats.

The vast [[supercontinent]] of [[Pangaea]] dominated the globe during the Triassic, but in the latest Triassic ([[Rhaetian]]) and Early Jurassic it began to gradually rift into two separate landmasses: [[Laurasia]] to the north and [[Gondwana]] to the south. The global climate during the Triassic was mostly hot and dry,<ref>{{cite web |url=http://news.nationalgeographic.com/news/2012/10/121018-triassic-extinctions-hot-global-warming-science-environment/ |archive-url=https://web.archive.org/web/20121020072805/http://news.nationalgeographic.com/news/2012/10/121018-triassic-extinctions-hot-global-warming-science-environment/ |url-status=dead |archive-date=October 20, 2012 |title='Lethally Hot' Earth Was Devoid of Life – Could It Happen Again? |date=19 October 2012 |website=nationalgeographic.com}}</ref> with deserts spanning much of Pangaea's interior. However, the climate shifted and became more humid as Pangaea began to drift apart. The end of the period was marked by yet another major mass extinction, the [[Triassic–Jurassic extinction event]], that wiped out many groups, including most pseudosuchians, and allowed dinosaurs to assume dominance in the Jurassic.