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Known as “The Great Dying,” the Permian–Triassic (P-T) extinction event, occurring about 252 million years ago, was Earth’s most severe extinction. It eliminated over 95% of marine species and 70% of terrestrial vertebrate species. The leading cause is believed to be massive volcanic eruptions from the Siberian Traps, which triggered catastrophic تغير المناخ, ocean anoxia, and acidification.
The Permian–Triassic extinction event represents the most profound biotic crisis in the Phanerozoic Eon. It marks the boundary between the Paleozoic and Mesozoic eras and fundamentally reset the course of evolution. The sheer scale of the extinction is staggering; it is the only known mass extinction of insects and it nearly ended life on Earth entirely. The recovery of life was also exceptionally slow, with “disaster taxa” like the hardy bivalve Claraia and the synapsid Lystrosaurus dominating depauperate ecosystems for millions of years. The primary culprit is identified as the Siberian Traps, a large igneous province (LIP) in modern-day Russia. Over a geologically brief period, massive flood basalt eruptions released an estimated 1.5 million cubic kilometers of lava.
This volcanism injected immense quantities of carbon dioxide, methane, and sulfur dioxide into the atmosphere. The CO2 and methane caused runaway global warming, while the SO2 led to intense المطر الحمضي. The warming of the oceans would have reduced their capacity to hold dissolved oxygen, leading to widespread marine anoxia (oxygen-depleted waters), evidenced by black shale deposits from this period. Furthermore, the absorption of atmospheric CO2 into the oceans caused severe acidification, making it difficult for marine organisms with calcium carbonate shells and skeletons (like corals, brachiopods, and mollusks) to survive. This combination of extreme heat, acid rain, ocean anoxia, and acidification created a global environmental catastrophe that very few species could withstand, leading to the “Great Dying.”
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