EndTriassic

EndTriassic, commonly referred to as the end-Triassic extinction event, is one of Earth's major mass extinctions. It occurred at the boundary between the Triassic and Jurassic periods, about 201.3 million years ago, and is characterized by a large biotic turnover across marine and terrestrial ecosystems. An estimated 70–80% of species disappeared, including many ammonites, conodonts, and other marine organisms, as well as numerous large reptile lineages. On land, ecological roles shifted as dinosaur lineages diversified and began to dominate in many environments. Floral communities also changed, with shifts in dominant plant groups.

The causes of the end-Triassic extinction are the subject of ongoing research and debate, but a leading hypothesis links the event to extensive volcanic activity associated with the Central Atlantic Magmatic Province (CAMP). The rapid emplacement of flood basalts would have released vast amounts of CO2 and other gases, driving global warming, ocean acidification, and reduced oceanic oxygen levels. Geological evidence includes a pronounced carbon isotope excursion in boundary deposits and traces of mercury and other elements associated with continental volcanism. Additional contributing factors may have included climate change, sea-level fluctuations, and ecological stress from changing habitats.

Recovery after the event took several million years. Dinosaurs persisted and diversified, becoming the dominant terrestrial vertebrates in the Jurassic, while the early, small mammals and other lineages continued to evolve in the aftermath. The end-Triassic extinction is a key reference point for understanding how rapid environmental change can reshape life on a global scale. Research combines stratigraphy, paleontology, and geochemistry to refine timing, magnitude, and causation, though some details remain unresolved.