Permian

EtymologyName formalityFormalUsage informationRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitPeriodStratigraphic unitSystemTime span formalityFormalLower boundary definitionFAD of the ConodontStreptognathodus isolatus within the morphotypeStreptognathodus wabaunsensis chronocline.Lower boundary GSSPAidaralash, Ural Mountains, Kazakhstan
50°14′45″N57°53′29″E / 50.2458°N 57.8914°E / 50.2458; 57.8914Lower GSSP ratified1996Upper boundary definitionFAD of the Conodont Hindeodus parvus.Upper boundary GSSPMeishan, Zhejiang, China
31°04′47″N119°42′21″E / 31.0798°N 119.7058°E / 31.0798; 119.7058Upper GSSP ratified2001

The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years, from the end of the Carboniferous Period 298.9 Ma (million years ago) to the beginning of the Triassic Period 251.902 Ma. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia.

The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids (reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed with the collision of Euramerica and Gondwana, during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors.

Various authors have proposed at least three, and possibly four major extinction events in the Permian, though the validity of some of these extinctions has been disputed. The end of the Early Permian (Cisuralian) was marked by a major faunal shift as most lineages of primitive "pelycosaur" synapsids became extinct, being replaced by more advanced therapsids during the Middle Permian (Guadalupian), though the nature of this transition (which may have been an extinction event dubbed "Olson's Extinction") is poorly understood. The end of the Capitanian Stage at the end of the Middle Permian was marked by the major Capitanian mass extinction event, associated with the eruption of the Emeishan Traps. The Permian (along with the Paleozoic) ended with the Permian–Triassic extinction event (colloquially known as the Great Dying), the largest mass extinction in Earth's history (which is the last of the three or four crises that occurred in the Permian), in which nearly 81% of marine species and 70% of terrestrial species died out, associated with the eruption of the Siberian Traps. It took well into the Triassic for life to recover from this catastrophe; on land, ecosystems took 30 million years to recover.