Jun 04, 2014 06:25 AM EDT
Earth’s First Mass Extinction Caused by Volcanic Eruptions in Australia, Study
An ancient volcanic eruption in Australia, some 510 million years ago, led to the world's first mass extinction, according to a study at the Curtin University.
Researchers said that the eruptions at Kalkarindji volcanic province in the Northern Territory and Western Australia covered an area of 2 million square kilometres of land in lava.
Associate Professor Fred Jourdan from Curtin's Department of Applied Geology said that Early-Middle Cambrian extinction from 510-511 million years ago destroyed 50 percent of the species. The extinction was considered to be caused by abrupt climatic changes and depletion of oxygen in the oceans.
But until now, researchers weren't able to determine the exact mechanism that triggered these changes.
"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," Jourdan said in a statement.
The researchers said that when the small volcano Pinatubo erupted in 1991, the sulphur dioxide emissions reduced the average global temperatures by a few tenths of a degree for a few years following the eruption. The ash and lava spewed from Pinatubo covered an area of 21 square miles, Live Science reports.
If small eruptions like Pinatubo can activate such drastic climate changes, then the impact from the volcanic province - almost the size of the State of Western Australia - would have been more severe. It caused the demise of nearly all multi-cellular life and creatures on Earth.
For the study, the researchers compared the volcanic eruptions at Kalkarindji volcanic province to volcanic regions elsewhere. They found that all mass extinctions were a consequence of sudden fluctuation in climate, caused by emissions of sulphur dioxide, greenhouse gases methane and carbon dioxide from volcanic eruptions.
"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," Jourdan said.
The study is published in the journal Geology.
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