Calibrating the End-Permian Mass Extinction.

The article discusses research into the chronology and possible causes of the mass extinction event at the end-Permian of the Phanerozoic era. Biodiversity data from sediments in South China was studied, including the mass spectrometric geochronological, isotopic, and biostratigraphic information from several sites. The results indicate that the mass extinction occurred in marine and terrestrial ecosystems 252.28 ± 0.08 million years ago over the course of 20,000 years or more, and point toward thermogenic carbon dioxide or methane emissions as possible causes of the extinction event.