The end-Permian extinction

The end Permian extinction was the greatest mass extinction of the Phanerozoic Era. It impacted marine and terrestrial plants and animals. Although the rate of the extinction has been controversial in the past, recent evidence suggests that the extinction progressed in two pulses approximately 5-12 million years apart. The second pulse of the extinction is marked by a sharp temperature spike and associated changes in carbon, oxygen, strontium and sulfur isotope ratios. There is evidence of severe marine anoxia and mass volcanic eruptions around this same time period. Many theories about the cause of the extinctions have been put forth. They include the possibility of volcanism, ocean anoxia, sea-level fluctuations and a bollide impact as the main triggering event. All these theories have evidence supporting them, but no single theory has gained universal acceptance. It is possible that the extinctions were caused by a series of events. Recent evidence suggests a mass extinction that occurred 2 million years ago was triggered by supernovae explosions within 130 light years of Earth. This paper discusses the possibility of a similar cause for the first pulse of the end-Permian extinction. Furthermore, it is suggested that recovery patterns from the first extinction pulse predisposed surviving species to extinction during the second pulse, when opposite environmental conditions were created by massive volcanism. The paper concludes by speculating about the role of extraterrestrial influences in initiating climate change and mass extinctions. THE END-PERMIAN EXTINCTION PAGE