Saturday, 7 January 2012

Another New Facet On The Permian Great Dying

An artist's impression of the baking ash fields caused
by the volcanic activity  of the  Permian Great Dying
Over the years palaeontologists have created a range of scenarios to explain the vast numbers of species which became extinct during the Permian Great Dying, ranging from extreme global warming, flood basalt events to fungal epidemics which destroyed whole forests and habitats. Theories, both plausible and preposterous, have come and gone, some of which rely upon well established principles.

Yet occasionally, the two sides come together to produce an incredibly strong hypothesis that has been overlooked for decades. 'No one had ever looked to see if mercury was a potential culprit,' says Dr. Steve Grasby, a research scientist at Natural Resources Canada and adjunct professor at the University of Calgary. 'This was a time of the greatest volcanic activity in Earth's history and we know today that the largest source of mercury comes from volcanic eruptions.'

'We estimate that the mercury released then could have been up to 30 times greater than today's volcanic activity, making the event truly catastrophic.' Normally micro-organisms, such as algae, bury mercury in the sediment, preventing any toxic build-up. However, Grasby and his team estimated that over 30 times more than the normal level would have been  released from the Earth's mantle, overwhelming the oceans and reducing the marine communities to something similar to the uninhabitable pools near smelting and metal processing plants.

The legendary toxicity of mercury, combined with flood basalt events and gas emissions, would explain why 95 % of marine life died out, not to mention the estimated 75 % of terrestrial fauna. 'We are adding to the levels through industrial emissions. This is a warning for us here on Earth today,' adds Benoit Beauchamp, Professor of Geology at the University of Calgary. The Great Dying was such a massive event, that it could only have had multiple causes, where each was very complex, but incredibly destructive.