‘Volcanic winter’ probably contributed to ecological disaster 250 million years ago – ScienceDaily


A team of scientists have identified an additional force that likely contributed to a mass extinction 250 million years ago. Its analysis of minerals in southern China indicates that the volcanic eruptions produced a “volcanic winter” that drastically lowered the earth’s temperatures – a change that added to the environmental effects resulting from other phenomena in the world. era.

The research, published in the journal Scientists progress, examined the Late Permian Mass Extinction (EPME), which was the most severe extinction event in the past 500 million years, wiping out 80 to 90 percent of species on earth and in the sea.

“Taking a closer look at the geological records around the time of the Great Extinction, we find that the late Permian global environmental catastrophe may have had multiple causes among marine and non-marine species,” said Michael Rampino, professor at New York University Biology Department and one of the authors of the article.

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 have caused environmental stresses, including significant global warming from volcanic releases of carbon dioxide and the associated reduction in oxygenation of ocean waters, the latter of which suffocates marine life.

The team for the Work on the progress of science, made up of more than two dozen researchers, including scientists from Nanjing University of China and the Guangzhou Institute of Geochemistry as well as the National Museum of Natural History of the Smithsonian Institution and State University de Montclair, examined other factors that may have contributed to the end of the Permian period, which stretched from 300 to 250 million years ago.

Specifically, they found minerals and related deposits on land in the southern region of China – including copper and mercury – whose age coincided with the late Permian mass extinction in localities. non-marine. Specifically, these deposits were marked by anomalies in their composition, possibly due to sulfur-rich emissions from nearby volcanic eruptions – they were covered with layers of volcanic ash.

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

The team’s findings suggest that the Siberian trap eruptions were not the only cause of the Late Permian mass extinction, and that the environmental effects of the eruptions in southern China and elsewhere may have played a vital role. in the disappearance of dozens of species. .

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