The explosive burning of coal seams in Siberia may have contributed to the mortality of marine organisms during the Permian mass extinction about 250 million years ago, suggests a paper online this week in Nature Geoscience. If coal fly ash — which is highly toxic — was propelled into the atmosphere in significant amounts, the subsequent fall-out into the oceans could have poisoned marine life.
Stephen Grasby and colleagues found a high concentration of charred particles in Permian-aged rocks from the Canadian High Arctic. The particles strongly resemble modern coal fly-ash — the lighter particles created during combustion — despite being located far from any source of coal. The researchers speculate that the coal came from Siberian coal seams. Siberia was subject to massive amounts of volcanism at the time of the Permian extinction, and it has been suggested that magma from the volcanism ignited the coal deposits in the surrounding area. The authors suggest that widespread coal explosions could have propelled fly-ash high into the atmosphere where it was dispersed globally.