page_title: Permian–Triassic extinction event
section_title: Supercontinent Pangaea
hierarchical_section_title: Permian–Triassic extinction event / Theories about cause / Supercontinent Pangaea
context_page_description: The Permian–Triassic extinction event, also known as the P–Tr extinction, the P–T extinction, the End-Permian Extinction, and colloquially as the Great Dying, formed the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras, approximately 252 million years ago. It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It was the largest known mass extinction of insects. Some 57% of all biological families and 83% of all genera became extinct.
  There is evidence for one to three distinct pulses, or phases, of extinction. Potential causes for those pulses include one or more large meteor impact events, massive volcanic eruptions, and climate change brought on by large releases of underwater methane or methane-producing microbes.
  The speed of the recovery from the extinction is disputed. Some scientists estimate that it took 10 million years, due both to the severity of the extinction and because grim conditions returned periodically for another 5 million years.
context_section_description: In the mid-Permian (during the Kungurian age of the Permian's Cisuralian epoch), Earth's major continental plates joined, forming a supercontinent called Pangaea, which was surrounded by the superocean, Panthalassa.
  Oceanic circulation and atmospheric weather patterns during the mid-Permian produced seasonal monsoons near the coasts and an arid climate in the vast continental interior.
  As the supercontinent formed, the  ecologically diverse and productive coastal areas shrank. The shallow aquatic environments were eliminated and exposed formerly protected organisms of the rich continental shelves to increased environmental volatility.
  Pangaea's formation depleted marine life at near catastrophic rates. However, Pangaea's effect on land extinctions is thought to have been smaller. In fact, the advance of the therapsids and increase in their diversity is attributed to the late Permian, when Pangaea's global effect was thought to have peaked.
  While Pangaea's formation certainly initiated a long period of marine extinction, its impact on the "Great Dying" and the end of the Permian is uncertain.
caption: Map of Pangaea showing where today's continents were at the Permian–Triassic boundary
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