Australia's Ancient Volcanic Eruptions Triggered First Mass Extinction

Australia's ancient volcanic eruptions are to be blamed for the first known mass extinction in history, a new study reveals.

A new Curtin University study found that the deadly eruption that took place in Australia some 510 million years ago greatly influenced the climate change that eventually led to the first mass extinction of complex life.

To prove the hypothesis, the researchers measured the age of the eruption of Kalkarindji volcanic province using radioactive dating techniques. The lava from this volcanic province engulfed almost 2 million square kilometer 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 were also able to measure a depletion of sulphur dioxide from the province's volcanic rocks -- which indicates sulphur was released into the atmosphere during the eruptions...."

The researchers explain that a small eruption in 1991 from the volcano Pinatubo released a large amount of sulphur dioxide that led to a drop in the average temperatures globally, by tenth of a degree for a few years after the eruption. 

They state that when a small eruption like Pinatubo triggered such a drastic effect on climate, then the impact from the volcanic province almost the size of the State of Western Australia would have been much more.

By comparing the Kalkarindji volcanic province with other volcanic provinces, the researchers proved that the eruption that occurred in the Early-Middle Cambrian extinction i.e. 510-511 million years ago, wiped out complex multicellular life.

The researchers say that  it was the rapid climate change and emission of sulphur dioxide from volcanoes that led to mass extinctions. 

"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.

The species found it difficult to battle against the rapidly changing climate that eventually led to the collapse of the species. This finding is important as it helps understand the current environment. To better understand long term climatic and biological effects of the gas in the atmosphere, it is necessary to study the ecosystem that affected the planet in the past.

Ancient volcanic eruptions not just caused the first mass extinction but they are also blamed for the extinction of Neanderthals paving way for modern humans to thrive in Europe and Asia, a study by University of Chicago reported.

The finding was documented in the journal Geology.