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.
Worst mass extinction shifted entire ecology of the world’s oceans
(11/23/2006) New research suggests that Earth’s greatest mass extinction did more than wipe out an estimated 95% of marine species and 70% of land species; it fundamentally changed the ecology of the world’s oceans.
Poisonous volcanic gas probably caused worst mass extinction says new study
(12/02/2005) The mass extinction event at the end of the Permian — where more than two-thirds of reptile and amphibian families perished and 95% of oceans life forms became extinct — was probably caused by poisonous volcanic gas, according to research published in the journal Geology. The researchers believe that volcanic gases from the eruption, near present day Siberia, depleted earth’s protective ozone layer and acidified the land and sea.
Global warming may have triggered worst mass extinction
(08/29/2005) A dramatic rise in carbon dioxide 250 million years ago may have caused global temperatures to soar and result in Earth’s greatest mass extinction, according to a study published in the September issue of Geology. Global warming, which may have produced temperatures 10 to 30 degrees Celsius higher than today, would have had a significant impact both on oceans, where about 95% of lifeforms became extinct, and on land, where almost 75% of species died out.