Scientists at Curtin University have shown that an ancient volcanic eruption in Australia 510 million years ago significantly affected the climate, causing the first known mass extinction in the history of complex life.
Published in prestigious journal Geology, Associate Professor Fred Jourdan from Curtin’s Department of Applied Geology, along with colleagues from several Australian and international institutions, used radioactive dating techniques to precisely measure the age of the eruptions of the Kalkarindji volcanic province – where lava covered an area of more than 2 million square kilometres in the Northern Territory and Western Australia.
“It has been well-documented that this extinction, which eradicated 50 per cent of species, was related to climatic changes and depletion of oxygen in the oceans, but the exact mechanism causing these changes was not known, until now,” Dr Jourdan said.
“Not only were we able to demonstrate that the Kalkarindji volcanic province was emplaced at the exact same time as the Cambrian extinction, but was also able to measure a depletion of sulfur dioxide from the province’s volcanic rocks – which indicates sulfur was released into the atmosphere during the eruptions.
“If relatively small eruptions like Pinatubo can affect the climate just imagine what a volcanic province with an area equivalent to the size of the state of Western Australia can do.”
The team then compared the Kalkarindji volcanic province with other volcanic provinces and showed the most likely process for all the mass extinctions was a rapid oscillation of the climate triggered by volcanic eruptions emitting sulphur dioxide, along with greenhouse gases methane and carbon dioxide.
“We calculated a near perfect chronological correlation between large volcanic province eruptions, climate shifts and mass extinctions over the history of life during the last 550 million years, with only one chance over 20 billion that this correlation is just a coincidence,” Dr Jourdan said.
Australia is famous for having most of the world’s dangerous and poisonous insects and animals but now we can add “First mass extinction” to our list. Now if only someone could finally document the bloodthirsty drop bears that plague our nation we would have it all.
Stay Curious – C.Costigan
