Geoscience

The Causes of Middle Permian Mass Extinction

A number of mass extinction events occurred over the course of Earth history. Volcanic eruptions associated with large igneous provinces (LIPs) are, in many cases, considered coeval to crises in global climate and mass extinctions. However, it is not yet certain whether the flood volcanism caused mass extinction. The relationship between the flood volcanism and the mass extinction yet remains to be resolved. Recently, Zhang Yan and her Ph.D. supervisor Prof. Ren Zhongyuan et al. measured sulfur contents in olivine-hosted melt inclusions in picritic lavas from the Emeishan large igneous province (LIP) and evaluated S degassing and its impact on the environment. The result shows that the S gas emitted during the formation of the Emeishan LIP could have led to the end-Guadalupian mass extinction. This is the first study on the end-Guadalupian mass extinction mechanisms using sulfur contents in olivine hosted melt inclusions. Based on S contents of melt inclusions and the residual S content of posteruptive basaltic lava, Prof. Ren’s research group of the State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, CAS, estimated the minimum amount of S released during the Emeishan flood volcanism, and discussed whether the emplacement of the ELIP was responsible for the Permian mass extinctions. The result indicates that the quick release of such a huge amount of volatiles into the atmosphere could have absorbed and reflected solar radiation, causing a temperature decrease and eventually leading to a “volcanic winter”. This scenario demonstrates that the Emeishan flood volcanism was responsible for the end-Guadalupian mass extinction. The results of this study have been published in the J. Geophys.Res. Solid Earth, 118, 4063–4070, doi:10.1002/jgrb.50324, Zhang, Y., Z.-Y. Ren, and Y.-G. Xu (2013), entitled Sulfur in olivine-hosted melt inclusions from the Emeishan picrites: Implications for S degassing and its impact on environment.