Two hundred and sixty million years ago the Earth experienced its worst mass extinction: 95 percent of marine life and 70 percent of terrestrial life vanished. Long a subject of dispute, researchers from the University of Leeds believe they have confirmed the reason behind the so-called Permian extinction.
A giant volcanic eruption in what is today’s Emeishan province in China unleashed half a million cubic kilometers of lava and tossed massive quantities of sulphur dioxide into the stratosphere 260 million years ago. The sulphur dioxide caused cloud formations across the entire planet. This cooled the Earth while subsequently dropping acid rain across the globe, leading to the planet’s most pervasive extinction.
“When fast flowing, low viscosity magma meets shallow sea it’s like throwing water into a chip pan – there’s spectacular explosion producing gigantic clouds of steam,” explains Professor Paul Wignall, a palaeontologist at the University of Leeds, and the lead author of the paper.
Fortunately, the researchers, publishing their findings in Science, were able to determine the exact time of the massive eruption in China, thereby linking it to the Permian extinction. Since the eruption occurred in a shallow sea it left a layer of igneous rock in-between two layers of sedimentary rock which were able to be identified with their epochs by their marine fossils.
“The abrupt extinction of marine life we can clearly see in the fossil record firmly links giant volcanic eruptions with global environmental catastrophe, a correlation that has often been controversial,” says Wignall.
The scientists believe their findings confirms several studies over the years that have suggested volcanic activity as the cause of the Permian extinction.
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