Mystery Deepens About Cause of Worst Mass Extinction Event on Earth, “The Great Dying”


Did volcanic eruptions trigger a “volcanic winter”? (Getty)

Earth’s worst mass extinction event was the “great death” 252 million years ago – long before the asteroid that killed the dinosaurs.

It is the most severe extinction in the past 500 million years, wiping out 80 to 90 percent of land and marine species.

Now, scientists have analyzed minerals in southern China that indicate the eruptions produced a “volcanic winter” that drastically lowered the Earth’s temperature, before a period of severe global warming.

Michael Rampino, a professor in the Department of Biology at New York University, says: “A closer look at the geological records around the time of the Great Extinction, we find that the global environmental catastrophe of the Late Permian may have taken a toll. multiple causes among marine environments and non-marine species.

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For decades scientists have studied what could have caused this global ecological catastrophe, with many pointing to the spread of vast lava floods through what are known as the Siberian traps – a vast region of volcanic rock in Russia’s province of Siberia.

These eruptions caused severe global warming due to volcanic releases of carbon dioxide and the associated reduction in oxygenation of ocean waters, which resulted in the suffocation of ocean life.

The team took into account other factors that may have contributed to the end of the Permian period, which stretched from 300 to 250 million years ago.

They found minerals and related deposits on land in the southern region of China (copper and mercury) whose age coincided with the late Permian mass extinction.

These deposits were marked by anomalies in their composition which were probably due to sulfur-rich emissions from nearby volcanic eruptions.

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Rampino says: “Atmospheric aerosols of sulfuric acid produced by the eruptions may have been the cause of a rapid global cooling of several degrees, before the severe warming observed throughout the mass extinction interval of the end. from the Permian.

Rampino says the environmental effects of the eruptions in southern China, and elsewhere, may have played a vital role in the extinction of dozens of species.

Recent research has shown that extinction did not happen at the same speed and that the process took much longer on land after many species died in the seas.

The research could have important implications for our current battle against climate change, the researchers warn.

Pia Viglietti, postdoctoral researcher at the Field Museum in Chicago, said: “People thought that because the marine extinction had occurred in a short period of time, life on earth should have followed the same pattern, but we found that marine extinction may in fact be a punctuation to a longer and more protracted event on land.

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Viglietti, Angielczyk and their colleagues examined the fossils of 588 four-legged fossil animals that lived in what is now the Karoo Basin in South Africa at the time of the Permian mass extinction.

The researchers created a database and separated the fossils by age, grouping the specimens at intervals of 300,000 years, allowing researchers to quantify the appearance and disappearance of different species and to gain an overview of the life over time.

Viglietti said, “Our approach unifies the data and says, okay, in this bin of time we have these species, but as we go up we have these other species. By applying sampling methods to these bins, we can help correct problems like having more or less specimens collected at different time intervals or in different locations. Ultimately, this allows us to quantify the magnitude of extinction and the speed with which new species appear.

“Instead of focusing too much on a single fossil, you are compiling hundreds of observations in roughly the same time frame.”

Fossils showed researchers that the Permian extinction was very different on earth than in the oceans, where it lasted only 100,000 years.

The extinctions on earth lasted ten times longer.

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