‘The Great Dying’: History's Worst Volcanic Eruption Killed Nearly All Life On Earth
Hundreds of millions of years ago, Mother Earth unleashed its wrath with a massive volcanic eruption that exploded continuously for almost 1 million years.
The "Great Dying" event, also called the End-Permian Extinction, was the largest mass extinction that ever occurred, wiping out nearly 90 percent of all life. For the first and last time since the first living organism appeared on the planet, Earth nearly lost all completely.
A Uniquely Cataclysmic Event
In a new study published in Nature Geoscience, researchers explain one of the reasons why the volcanic eruption known as the Siberian Flood Basalts turned out to be so much more catastrophic than other volcanic activities that have occurred.
The eruption, which took place in what is now Siberia, Russia, happened 252 million years ago, and the world hasn't seen a similar event since.
"The scale of this extinction was so incredible that scientists have often wondered what made the Siberian Flood Basalts so much more deadly than other similar eruptions," Michael Broadley, the lead study author, says in a statement.
Halogen Reserves Add To Great Dying's Lethality
According to Broadley, who is a postdoctoral researcher at the Centre for Petrographic and Geochemical Research in France, he, his late co-author Lawrence Taylor, and the rest of the team analyzed samples of mantle xenoliths, which are rocks from the lithosphere captured by magma and ejected along with the lava when the volcano erupts.
With these samples, the researchers were able to identify the composition of the lithosphere. Before the million-year-long explosion, the Siberian lithosphere was packed with halogen chemicals including chlorine, bromine, and iodine. After the Great Dying, these elements were no longer found there.
As Motherboard reports, halogens are a family of elements that include gases that can be very toxic. Some are even deadlier when combined with other molecules, making the release of massive amounts extremely dangerous.
The gases, the authors say, were spewed out from the volcanoes, making its way to the ozone layer and destroying the protective shield. This allowed deadly amounts of ultraviolet radiation to make its way to the Earth's surface and spur the extinction of most of the planet's living species.
"We concluded that the large reservoir of halogens that was stored in the Siberian lithosphere was sent into the earth's atmosphere during the volcanic explosion, effectively destroying the ozone layer at the time and contributing to the mass extinction," Broadley explains.