Volcanoes spewed mercury that spurred The Great Dying 300,000 years ago

More than 250 million years ago, the biggest extinction event ever occurred – it’s called The Great Dying. This event lasted around 300,000 years.and killed off more than 90 percent of marine species and 70 percent of species of animals on land. Rocks from all over the world that formed around that time contain high levels of mercury.

Researchers at the Geological Survey of Canada, including Steven Grasby, have modeled how much mercury the volcanoes of Siberia put off as they erupted during the extinction.

As those volcanoes erupted near the Permian-Triassic boundary, the eruptions spewed lava that released massive amounts of mercury. That mercury dropped into the ocean or settled in the land and then washed into the sea, according to models created by Grasby and his team.  They believe that one form of mercury could have been more than 450 times the normal levels on land and in the sea.

Animals around the world would have been exposed to the mercury which may partially explain The Great Dying. 

By exploring the levels of mercury scientists hope to learn more about the worldwide nature of the extinction.