New research, supported in part by the NASA Exobiology and Evolutionary Biology (Exo/Evo) program, shows that mass extinctions need not be sudden events. In an extensive investigation of rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic, the team revealed that Earth’s deadliest-known mass extinction took place in stages over hundreds of thousands of years.

The “Great Dying” occurred roughly 252 million years ago at the end of the Permian period, and resulted in the loss of 90 percent of Earth’s marine life. The evidence suggests that the event was linked to massive volcanism in a region of Siberia known as the “Siberian Traps”. Lava from this volcanic activity flowed through a large coal deposit, releasing vast quantities of the greenhouse gas methane. The devastating effects were confined to the northern latitudes at first, but reached tropical latitudes after the eruptions were in full swing.

The report, “Evidence for a diachronous Late Permian marine crisis from the Canadian Arctic region,” was published in the Geological Society of America Bulletin under lead author Thomas J. Algeo. The research was supported by the National Science Foundation, Canadian Natural Sciences and Engineering Research Council and the Exo/Evo element of the NASA Astrobiology Program.