“Volcanic winter” contributed to ecological disaster 250 million years ago

A team of scientists has identified an additional force that may have contributed to the mass extinction event 250 million years ago. Analysis of minerals in southern China showed that volcanic eruptions caused a “volcanic winter” that dramatically lowered the Earth’s temperature, a change that added to the ecological effects caused by other phenomena at the time.

The study, published in Science Advances, examines the Permian Mass Extinction Event (EPME), which was the most severe extinction event of the past 500 million years, wiping out 80 to 90 percent of species on land and in the sea.

“As we take a closer look at the geologic record of the timing of the great extinction, we are coming to the conclusion that the global environmental disaster of the late Permian period may have had multiple causes among marine and nonmarine species,” says Michael Rampino, a professor in New York University’s Department of Biology and one of the paper’s authors.

For decades, scientists have been figuring out what might have caused this global environmental disaster, and many have pointed to the spread of huge lava flows through the so-called Siberian Trap, a large region of volcanic rocks in the Russian province of Siberia. These eruptions have caused environmental stresses, including severe global warming due to volcanic carbon dioxide emissions and a related decrease in oxygen saturation of ocean waters – the latter resulting in a suffocation of marine life.

The team working on the paper in Science Advances, consisting of more than two dozen researchers, including scientists from Nanjing University of China and the Guangzhou Institute of Geochemistry, as well as the Smithsonian Institution’s National Museum of Natural History and Montclair State University, looked at other factors that may have contributed to the end of the Permian, which lasted from 300 to 250 million years ago.

In particular, they found onshore deposits of minerals and related substances – particularly copper and mercury – in the southern China region, whose age coincided with the end of the Permian mass extinction in non-Marine sites. In particular, these deposits were marked by composition anomalies, probably due to sulfur-rich emissions from nearby volcanic eruptions-they were covered by layers of volcanic ash.

“Atmospheric sulfuric acid aerosols from the eruptions may have been responsible for the rapid global cooling of several degrees that preceded the dramatic warming seen at the end of the Permian mass extinction period,” explains Rampino.

The team’s findings suggest that eruptions in the Siberian Trap were not the sole cause of the Permian mass extinction, and that the ecological effects of eruptions in southern China and elsewhere may have played an important role in the extinction of dozens of species.

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