Volcanic eruptions behind 'Great Extinction': study

Massive volcanic eruptions in Siberia may have triggered the Great Permian Extinction about 250 million years ago, according to a study that mapped chemical fingerprints ranging from the Arctic to India.

Researchers from New York University (NYU) in the US found that volcanic eruptions led to catastrophic environmental changes that led to the disappearance of more than 90 per cent of all species on the Earth.

They found a global spike in the chemical element nickel at the time of extinction.

The anomalous nickel most likely came from emanations related to the concurrent huge volcanic eruptions in what is now Siberia, researchers said.

These eruptions are associated with nickel-rich magmatic intrusions - rocks formed from the cooling of magma - that contain some of the greatest deposits of nickel ore on the planet.

The study, published in the journal Scientific Reports, used an Inductively Coupled Plasma Mass Spectrometer, which measures the abundance of rare elements at their atomic level.

Researchers documented anomalous peaks of nickel in regions ranging from the Arctic to India at the time of the Great Permian Extinction - distributions that suggest these nickel anomalies were a worldwide phenomenon.

This new evidence of a nickel fingerprint at the time of the extinctions shows that it was the volcanic upheaval in Siberia that produced intense global warming and other environmental changes that led to the disappearance of more than 90 per cent of all species, researchers said.

"The Siberian volcanic eruptions and related massive intrusions of nickel-rich magmas into the Earth's crust apparently emitted nickel-rich volatiles into the atmosphere, where they were distributed globally," said Michael Rampino, geologist at NYU.

At the same time, explosive interactions of the magma with older coal deposits could have released large amounts of carbon dioxide and methane, two greenhouse gases, which would explain the intense global warming recorded in the oceans and on land at the time of the mass extinctions, researchers said.

"The warm oceans also became sluggish and depleted in dissolved oxygen, contributing to the extinction of many forms of life in the sea," Rampino said.