The Triassic was the first geological period of the Mesozoic Era. It lasted from 252.2 to 201.3 million years ago.



Pangaea as it appeared in the Triassic, with modern continents illustrated

During the Triassic, all the modern continents were joined together in a single supercontinent called Pangaea, and surrounded by the ocean of Panthalassa. Pangaea was already starting to break up during the Triassic, but not to a point where the landmasses actually separated. This first rift started to move modern-day Morocco and New Jersey apart, which would later expand and form the Atlantic Ocean.[1]


The climate of the Triassic was generally hot and dry, though there were a few tropical regions around the equator.[2] There is no evidence of glaciation at the poles during this time; rather, the climate in this part of the world was mild and temperate.[3]


The main types of plant during the Triassic included cycads, horsetails, and ginkgo trees. In the southern hemisphere, Glossopteris was the dominant tree during the Early Triassic.[4]


The Permian-Triassic extinction devastated all forms of life, and ecosystems around the world took a long time to reestablish themselves.[5] Among other things, the first ammonites, frogs, turtles, plesiosaurs, ichthyosaurs, crocodylians, pterosaurs, dinosaurs (such as Nyasasaurus, Eoraptor, and Herrerasaurus), and true mammals evolved during the Triassic.[6]


The Triassic ended with a mass extinction, the Triassic-Jurassic extinction event. Although it affected the whole planet, it most severely affected the oceans, as roughly half of the marine genera went extinct. On land, several types of reptiles that were dominant during the Permian and Early Triassic went extinct, leaving the dinosaurs to become the dominant form of land animal during the Jurassic. The cause of this extinction is not known with certainty.[7]


  2. Preto, N.; Kustatscher, E.; Wignall, P.B. (2010). "Triassic climates — State of the art and perspectives". Palaeogeography, Palaeoclimatology, Palaeoecology 290: 1–10. doi:10.1016/j.palaeo.2010.03.015.
  3. Stanley, Steven M. Earth System History. New York: W.H. Freeman and Company, 1999. ISBN 0-7167-2882-6
  4. McLoughlin, S., Lindström, S. & Drinnan, A.N. 1997. Gondwanan floristic and sedimentological trends during the Permian-Triassic transition: new evidence from the Amery Group, northern Prince Charles Mountains, East Antarctica. Antarctic Science, 9: 281-298.
  5. Sahney, S. and Benton, M.J. (2008). "Recovery from the most profound mass extinction of all time" (PDF). Proceedings of the Royal Society: Biological 275 (1636): 759–65. doi:10.1098/rspb.2007.1370. PMC 2596898. PMID 18198148.
  6. Douglas Palmer & Peter Barrett (2009). Evolution: The Story of Life. London, Britain: The Natural History Museum. ISBN 9781845333393.
  7. No Significant Nonmarine Carnian-Norian (Late Triassic) Extinction Event: Evidence From Petrified Forest National Park

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