Scientists Find Evidence That Earth’s Largest Mass Extinction Was Caused by Volcanoes

Earth has witnessed five known mass extinctions over 4.5 billion years.

Scientists have found conclusive evidence suggesting that volcanoes are responsible for the biggest mass extinction our planet ever faced.

According to experts, mercury buried in ancient rock is the ultimate clue that suggests Earth’s volcanoes kickstarted the largest mass extinction in the history of our planet. The new study was published in the journal Nature Communications.

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It all happened around 252 million years ago. Then, Earth went through a catastrophic live-devouring phase that was so dramatic and widespread that scientists call it “the Great Dying.”

The catastrophe killed more than 95 percent of life on Earth over hundreds of thousands of years.

Now, paleontologists from the University of Cincinnati and the China University of Geosciences have discovered in more than a dozen sites around the world, mercury embedded into ancient rocks.

This, say researchers, is the ultimate evince that points towards the fact that volcanic eruptions were to blame for the greatest mass extinction the world ever faced.

According to experts, volcanic eruptions produced massive fires, ignited as massive deposits of coal started burning. This released large amounts of Mercury into our planet’s atmosphere.

“Typically, when you have large, explosive volcanic eruptions, a lot of mercury is released into the atmosphere,” said Thomas Algeo, a professor of geology in UC’s McMicken College of Arts and Sciences.

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“Mercury is a relatively new indicator for researchers. It has become a hot topic for investigating volcanic influences on major events in Earth’s history,” Algeo added.

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Eventually, the Mercury reached the atmosphere, but then started raining down onto the surface, and into marine sediments, leaving traces of a catastrophic time.

Jun Shen, an associate professor at the China University of Geosciences. and lead author of the new study explained that “Volcanic activities, including emissions of volcanic gases and combustion of organic matter, released abundant mercury to the surface of the Earth.”

This chain of events eventually changed the world, killing most of the terrestrial and marine life that had developed until then.

The set of eruptions took place in modern-day Siberia, in a volcanic system referred to as the Siberian Traps.

Experts say that most of the volcanic eruptions took place through gaping fissures in the ground, and not in cone-shaped volcanoes. These eruptions catapulted as much as million cubic kilometers of ash high into the air over extended periods. The eruptions also filled the atmosphere with greenhouse gasses, which caused the entire planet to heat up by around 10 degrees centigrade.

Furthermore, scientists say that these volcanic eruptions were persistent, frequent and their fury spanned a period of hundreds of thousands of years. This means that the mass extinction did not occur in a short period, but was a domino effect that eventually annihilated most of the life on the planet.

“It’s not necessarily the intensity but the duration that matters,” Algeo said. “The longer this went on; the more pressure was placed on the environment.”

Source
Phys.org