The end-Permian mass extinction: a still unexplained catastrophe.

The authors reflect on mass extinction at the end of Permian period. Topics discussed include causes of mass extinction such as Siberian flood basalt volcanism, marine anoxia and euxinia and biogenic methane release due to explosive growth of a methanogenic microbe; evidence of a cyanobacterial bloom at Meishan; and association of the Triassic recovery with a number of repeated large carbon isotope excursions.