Biggest Extinction Event Caused by Volcanoes
The Permian-Triassic extinction event – also known as the Great Dying – is recorded as the most significant extinction event in Earth’s history, seeing a whopping 96% of marine species killed off, 70% of land-based animals, and is the only extinction event to have affected insects.
Researchers at the University of Calgary believe that they have discovered evidence that supports their claim that volcanoes are the direct cause of this extinction event, which took place some 250 million years ago.
“This could literally be the smoking gun that explains the latest Permian extinction,” says Dr. Steve Grasby, adjunct professor in the U of C’s geoscience department and research scientist at Natural Resources Canada.
Grasby and colleagues found layers of coal ash in Canada’s High Arctic that suggest that volcanoes burnt significantly large amounts of coal which, in turn, caused massive amounts of ash to be ejected into the atmosphere, having a broad impact across land and ocean.
“Our research is the first to show direct evidence that massive volcanic eruptions—the largest the world has ever witnessed—caused massive coal combustion thus supporting models for significant generation of greenhouse gases at this time,” says Grasby.
“It was a really bad time on Earth. In addition to these volcanoes causing fires through coal, the ash it spewed was highly toxic and was released in the land and water, potentially contributing to the worst extinction event in earth history,” added Grasby.
At the time of the extinction, planet Earth had only one land mass, the supercontinent now known as Pangaea. The volcanoes that erupted are now found in northern Russia, centred around the Siberian city of Tura, and totalling just under two million square kilometres, a size that is larger than that of Europe.