The story
About 260 million years ago, at the end of the Capitanian Age, a mass extinction struck, sometimes called the end-Guadalupian extinction. In tropical seas it removed many reef builders, fusulinid foraminifera and brachiopods, especially in the Tethys Ocean. On land, the large dinocephalian therapsids, which had been the largest animals of their time, disappeared, as the Karoo Basin record of South Africa, studied by Michael Day, Bruce Rubidge and colleagues in 2015, shows.
The likely trigger was the Emeishan flood basalts of southwestern China, which erupted about this time and released large amounts of gases that may have cooled and then warmed the climate and acidified seas. The severity is argued: some estimates give strong losses, but later reviews suggest the marine toll was smaller than first thought. The event is a precursor to the Great Dying about 8 million years later and set up the late Permian world with gorgonopsians and dicynodonts. Together, the two crises show repeated volcanic stress on a world already shaped by the supercontinent Pangaea.
Why it mattered
- It cleared the large dinocephalians and made room for gorgonopsians and dicynodonts in the Late Permian.
- It shows volcanic eruptions can drive extinctions in both sea and land.
- It forms an early stage of the long crisis that ended with the Great Dying.
Sources
- The Late Capitanian Mass Extinction of Terrestrial Vertebrates in the Karoo Basin of South Africa Frontiers in Earth Science (Day and Rubidge 2021)
- Day et al. 2015, high-precision U-Pb age of the Capitanian extinction in the Karoo Basin Proceedings of the Royal Society B
- The Middle Permian (Capitanian) mass extinction on land and in the oceans Earth-Science Reviews (Bond et al. 2010)
- The double mass extinction revisited: reassessing the severity, selectivity, and causes of the end-Guadalupian biotic crisis Paleobiology (Clapham et al. 2009)
Contested history
Consensus: A biotic crisis occurred at the end of the Capitanian, near the time of Emeishan volcanism; its size and cause are debated.
- The Middle Permian (Capitanian) mass extinction on land and in the oceans Earth-Science Reviews (Bond et al. 2010)
- Day et al. 2015, high-precision U-Pb age of the Capitanian extinction in the Karoo Basin Proceedings of the Royal Society B
- The double mass extinction revisited: reassessing the severity, selectivity, and causes of the end-Guadalupian biotic crisis Paleobiology (Clapham et al. 2009)
- The Late Capitanian Mass Extinction of Terrestrial Vertebrates in the Karoo Basin of South Africa Frontiers in Earth Science (Day and Rubidge 2021)
- The Middle Permian (Capitanian) mass extinction on land and in the oceans Earth-Science Reviews (Bond et al. 2010)
Community notes
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