Research by a University of Queensland geologist is unlocking the ancient secrets of a period of Earth's history when the world was wracked by massive volcanic eruptions.
Dr Scott Bryan, from UQ's Sustainable Minerals Institute, together with colleague Dr Ingrid Ukstins Peate, from the University of Iowa, travelled to China's Emeishan province to study what is believed to be the remnants of one of the world's most unstable periods.
"These eruptions occurred around 260 million years ago and heralded in a new period in Earth's history of supercontinent break-up and mass extinctions," he said.
"To give you an idea of the scale of these eruptions, the eruption of Mount St Helens in America in 1980 released just over one cubic kilometre of magma.
"Eruptions in the Emeishan province probably evacuated anywhere between 100 and 5,000 cubic kilometres of magma.
"And it was not just one eruption but tens to hundreds, all occurring within a million years or so, each one just huge."
He said these types of eruptions would have had a massive impact, not just on the surrounding area, but potentially on the whole world.
"This igneous event in China has been argued to have been the trigger for climate change and an important mass extinction event in Earth's history approximately 260 million years ago," he said.
Dr Bryan, a third generation geologist, who now works for the SMI's W.H. Bryan Mining and Geology Research Centre - named after his grandfather - said the study also found these catastrophic eruptive events were not likely to have been caused by mantle plumes, as is widely thought.
"This area has previously been believed to be the best example of mantle plume-triggered volcanic activity, where rapid surface uplift over a kilometre high occurred in response to the mantle plume rising up from more than 2000 km deep within the Earth" he said.
"What we found was the first massive eruptions resulted from basaltic magma reacting fiercely and explosively with the shallow marine sea that had previously existed in southwestern China for millions of years.
"This explosive style of volcanism may have also provided a more efficient mechanism for volcanic gases to reach the stratosphere and drift around the world to cause climate change and the mass extinction event at 260 million years ago."
The research was published this week in the prestigious scientific journal Nature Geoscience, doi: 10.1038/ngeo281.
Media: Dr Scott Bryan (07 3346 4152 or 0437 036 347; international +61 7 3346 4152 or +61 437 036 347) or Andrew Dunne at UQ Communications (07 3365 2802 or 0433 364 181; international +61 7 3365 2802 or +61 433 364 181). Photos of Dr Bryan on location in China and in the lab are available by contacting UQ's Photo Librarian on 07 3365 2753; international +61 7 3365 2753.
