Volcanic Coal Burning Found to Have Caused the Largest Mass Extinction in History

A new study showed evidence of how coal burning following a volcanic eruption caused climate change in Siberia. The research was spearheaded by Lindy Elkins-Tanton, a professor from the Arizona State University (ASU) School of Earth & Space Exploration, who discovered the first direct evidence of how extensive burning of coal in Siberia caused the Permian-Triassic Mass Extinction Event. This event is believed to be the worst and most severe case of mass extinction in the history of the Earth. Geologists call this event "the Great Dying." Their study was published recently in Geology.

The research team looked at the volcaniclastic rocks found in the Siberian Traps. The eruptive event is among the most significant volcanic events known by scientists within the past half-billion years. These eruptions occurred for about two million years more, spanning the boundary of the Permian-Triassic periods. A basaltic rock presently covers this area for roughly 3,000,000 m2.

The Permian-Triassic mass extinction almost extinguished life on our planet around 252 million years in the past, with a maximum of 96% of marine life and 70% terrestrial vertebrates snuffed out.

Researchers calculated the temperature of marine waters at the time extinctions were at their peak, and results showed that the planet was in a scorching lethal temperature level, with ocean and sea temperatures around the equator surpassing 104º F. Ecosystems and plant and animal species needed millions of years to establish a new balance and recover populations.

One hypothesized cause of the event involves massive coal burning, which led to extreme global warming and extinguished most life forms. The team of Elkins-Tanton set out to look for evidence of this theory and began to study the region of the Siberian Traps, where magma and lava are known to have burned coal and vegetation.

In the Angara River, the team found high cliffs of volcaniclastic rocks that line the river for many hundreds of miles. They studied the structures for six years, flying to remote areas by helicopter, floating on rivers, and hiking across forests to collect rocks. More than a thousand pounds of rock samples were collected and shared with a scientific team composed of 30 members coming from eight countries.

Upon analysis, they found strange fragments that seemed to be burnt wood and coal. With further fieldwork, they collected even more rocks from other sites that had coal, charcoal, and sticky blobs rich with organic matter.

Co-author Steve Grasby from the Geological Survey of Canada had previously found similar microscopic burnt coal material on an arctic island in Canada, which also dated from the end of the Permian Period and were believed to have drifted to the area from Siberia.

The team found evidence that magmas in the Siberian Traps incorporated the coal and other organic materials, which means the magmas burned large volumes of these coals and other organic matter in the eruptions.

Parallel events also occur today, with human burning of coal and hydrocarbons, sulfur acid rain, and ozone-destroying halocarbons. Elkins-Tanton says this is an extra incentive for us to act now. Indeed, taking action may prevent or at least cushion another mass extinction event.