Permian–Triassic extinction event

A global mass extinction about 252 million years ago that eliminated most marine species and many terrestrial species. It was the most severe known extinction in Earth’s history.

Siberian Traps: A vast volcanic province in Siberia formed by enormous eruptions around the end of the Permian Period. Its eruptions released gases and heat implicated in the extinction’s global environmental disruption.
Trilobite: An extinct marine arthropod group whose members had segmented bodies and distinctive compound eyes. The last trilobites disappeared during the end-Permian extinction.
U–Pb dating: A radiometric dating method that uses the decay of uranium isotopes into lead to determine mineral ages. It established the close timing of Siberian eruptions and the extinction.
Triassic recovery fauna: The animal communities that repopulated ecosystems after the end-Permian mass extinction. These communities show how slowly and unevenly ecosystems recovered.
Extinction selectivity: The nonrandom pattern of extinction in which some organisms are more likely to disappear than others. Researchers compare which traits predicted survival across marine and terrestrial groups.
Siberian Traps large igneous province: The extensive accumulation of volcanic rock produced by eruptions across Siberia near the Permian–Triassic boundary. Its scale and timing anchor the leading volcanic explanation for the extinction.
Rugose coral: An extinct group of corals, often called horn corals, that built solitary or colonial skeletons. Rugose corals vanished as reef ecosystems collapsed at the boundary.
Carbon isotope excursion: A marked change in the ratio of carbon isotopes recorded in rocks or fossils. A major excursion at the boundary signals disruption of the global carbon cycle.
Lazarus taxon: A group that disappears from the fossil record for an interval and later reappears. Fossil gaps after the crisis can reflect rarity or poor preservation rather than true extinction.
Volcanic winter: A period of global cooling caused when volcanic aerosols reduce the sunlight reaching Earth’s surface. Short-lived volcanic cooling may have accompanied, but cannot alone explain, prolonged warming.

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