The 'Great Dying' of 250 million years ago — which wiped out 90 per cent of living species — was driven in part by an eruption that generated a global volcanic winter. 

Thus concludes research led by the Chinese Academy of Sciences, who studied contemporary copper-rich deposits from the Sichuan province of south China.

Anomalies in these rocks — which were covered by layers of volcanic ash — suggest that they were formed or affected by sulphur-rich emissions from nearby volcanoes.

When injected into the atmosphere, sulphur aerosols act to reflect incoming sunlight back into space and modify clouds, resulting in a rapid cooling effect. 

The researchers believe that volcanism in China could have temporarily lowered average global temperatures by some 4°C (7.2°F).

The team suggest that the sulphur-rich volcanism may have been a previously unknown stressor in the build-up to the End-Permian extinction 250 million years ago — contributing to the loss of species in this devastating event.

'As we look closer at the geologic record at the time of the great extinction,' began paper author and geologist Michael Rampino of New York University.

'We are finding that the end-Permian global environmental disaster may have had multiple causes among marine and non-marine species.'

The End-Permian extinction is commonly linked to different volcanic activity — specifically the eruption of flood basalts that make up Russia's vast Siberian Traps.

Rather than a brief, explosive episode, the formation of this 'large igneous province' saw some 1 million cubic miles (4 million cubic kilometres) of rock emplaced in the form of runny lava over the course of two million years.

These eruptions are thought to have caused considerable environmental stress — including severe global warming resulting from the release of carbon dioxide and a reduction in the oxygen content of oceans, suffocating marine life.