Permian Extinction Revisited

The end-Permian mass extinction: a still unexplained catastrophe

Authors:

Shen

Abstract:

The end-Permian mass extinction is widely regarded as the largest mass extinction in the past 542 million years with loss of about 95% of marine species and 75% of terrestrial species. There has been much focus and speculation on what could have caused such a catastrophe. Despite decades of study, the cause or causes remain mysterious. Numerous scenarios have been proposed, including asteroid impact, Siberian flood basalt volcanism, marine anoxia and euxinia, sea-level change, thermogenic methane release and biogenic methane release due to explosive growth of a methanogenic microbe.

It is now clear that a number of major environmental perturbations are approximately coincident with the end-Permian mass extinction. These include global negative excursions of both δ13Ccarb and δ13Corg near the extinction interval (see a review by Korte and Kozur [1] and a recent study by Shen et al. [2]); distinctive calcium isotope excursions [3]; a sudden expansion of microbialites [4]; a rapid temperature rise of ∼8°C in the extinction interval [5] followed by a long ‘hothouse’ period in the Early Triassic [6], large regression followed by rapid transgression [7], evidence for wildfires and cyanobacteria blooms [8], etc. There remains disagreement over the nature, timing and duration of the environmental perturbations and how they relate to detailed patterns of extinction, resolution of which is critical for understanding the causative mechanism(s).