The largest mass extinction on Earth has seen most lives wiped out in the blink of an eye

About 252 million years ago, most scientists discovered that life on Earth had disappeared in the blink of an eye, even in just 3,000 years.

The mass extinction – known as the "great moribund" – was the worst in Earth's history, erasing about 90% of the planet's species, but our understanding of its course and duration is fuzzy . The causes include one or more impact events, a sudden release of methane from the seabed and a period of intense volcanism.

The latter has recently gained popularity. Last month, scientists discovered that a million-year-old volcanic eruption along the Siberian Trapps may have altered the atmosphere and the ozone layer, preventing life from surviving.

In a study published in the Bulletin of the Geological Society of AmericaThe researchers have now managed to reduce the delay for the great death, finding that life was gone in a window of 31,000 years. And Shen Shuzhong, lead author of the newspaper, said Newsweek that 31 000 of them constitute the upper limit of extinction – the actual period was probably close to 3 000 years.

In addition, they found that this period coincided with a single volcanic event that would have made the Earth very difficult to live with – heavy metals pollute the atmosphere, the ocean lacks oxygen, and acid rain floods.

The researchers focused their attention on a region of southern China. They performed radiometric dating of closely layered volcanic materials, a process that allows scientists to determine when an event has occurred. But after 252 million years, these layers are usually quite condensed and difficult to analyze.

In the study, the team examined Penglaitan sediments, which accumulated 100 times faster than other comparable beds. This means that the sediment is much thicker and can be examined in more detail.

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Outcrop photos of the Permian-Triassic border interval at Penglaitan. NIGPAS

In sediments, they found 66 species in one section. Their analysis showed that 29 of them had disappeared in an extremely short period of time. Essentially, scientists found that a variety of species existed, and they did not, and that this change occurred on a time scale of no more than 31,000 years.

The authors say that prolonged eruptions to Siberian Trapps 420,000 years before extinction have probably put the Earth in an extremely fragile state. A major eruption then caused a complete collapse of the planet's ecosystems and massive extinction occurred.

Shuzhong, of the Chinese Academy of Sciences, said the discovery that mass extinction was almost instantaneous, geologically speaking, was a big surprise. "The extinction is really much faster than ever. This corresponds to a single volcanic event and is probably no more than 3,000 years old. "

The severity of the event in the southern region of China studied was also unexpected. Normally, some species survive during the event until the Triassic Period – a group called the Survival Taxa.

"But in this section, almost no Permian species survived in the Triassic, which means that under certain environmental conditions, extinction could eliminate almost all species in the Permian ecosystem," said Shuzhong.